ELECRAFT K1 TRANSCEIVER

BAND

WPM +

E LECRA F T
RIT/XITTXDISPLAY

RX

MENU

ATTEN

1

FILTERWPM -K 1 TR ANS C EIVER
EDIT

+

2

ATTEN

AF GAIN

RIT

-

MSG

+
XIT

TUNE

O W N E R’S M A N U A L

ELECRAFT K1Multiband
CW Transceiver
Owner’s Manual
Revision J, March 24, 2015
Copyright  2015 Elecraft, LLC
All Rights Reserved

Elecraft  www.elecraft.com

P.O. Box 69  Aptos, CA 95001-0069(831) 763-4211  Fax: (831) 763-4218

ELECRAFT

2

Table of Contents
1.

INTRODUCTION.................................................................................................................................................................................... 3

2.

SPECIFICATIONS ................................................................................................................................................................................ 5

3.

PREPARATION FOR ASSEMBLY.................................................................................................................................................... 6

4.

FILTER BOARD.................................................................................................................................................................................. 115.

FRONT PANEL BOARD.................................................................................................................................................................... 176.

RF BOARD, PART I........................................................................................................................................................................... 25

7.

ALIGNMENT AND TEST, PART I ...................................................................................................................................................... 368.

RF BOARD, PART II.......................................................................................................................................................................... 42

9.

ALIGNMENT AND TEST, PART II..................................................................................................................................................... 46

10.

FINAL ASSEMBLY............................................................................................................................................................................ 48

11.

OPERATION....................................................................................................................................................................................... 50

12.

CIRCUIT DETAILS............................................................................................................................................................................. 58

PARTS LIST.............................................................................................................................................................................APPENDIX ASCHEMATIC.............................................................................................................................................................................APPENDIX BBLOCK DIAGRAM..................................................................................................................................................................APPENDIX CPHOTOGRAPHS.....................................................................................................................................................................APPENDIX D
TROUBLESHOOTING............................................................................................................................................................APPENDIX EPARTS PLACEMENT DRAWINGS....................................................................................................................................... APPENDIX FQUICK REFERENCE..............................................................................................................................................................APPENDIX GELECRAFT

3

1. Introduction
The K1 is a versatile, low-power CW transceiver that covers two
or four builder-selected HF bands. It provides 5 watts or more of
power output; excellent receiver sensitivity and selectivity; andmany useful operating features, including instant band selection,
receive and transmit incremental tuning (RIT/XIT), digital
display, configuration menu, and multiple crystal filter
bandwidths.

Like our all-band K2 transceiver, the K1 uses modular construction,
allowing it to adapt to your operating needs. The Filter board covers
either two (KFL1-2) or four (KFL1-4) bands, and a different Filter
board can be swapped in at any time. There are two plug-in options,
including a noise blanker (KNB1) and automatic antenna tuner(KAT1). There's also an internal AA-cell battery option (KBT1).
These options can be installed easily at any time.

With receive-mode current drain of about 55 mA, built-in keyer,
and a stable, low-frequency VFO, the K1 is ideal for portable
operation. It's also one of the smallest multi-band HF transceivers
available–smaller than many single-band rigs. And, when used withthe optional wide-range tilt stand (KTS1), the K1 is truly trailfriendly. The tilt stand comes with long arms for ground-mounting(see below), as well as shorter arms for desk-top use.

The K1's modular assembly will also appeal to first-time builders.
The kit requires almost no point-to-point wiring, unlike earlier
designs that used wiring harnesses. The K1 even provides its own
built-in test equipment, including battery voltage monitor,
wattmeter, and frequency counter. The manual provides complete
troubleshooting and signal tracing procedures, and you’ll find further
support on our website, www.elecraft.com.
We’d like to thank you for choosing the K1 transceiver, and hope itmeets your expectations for operation both at home and in the field.
Wayne Burdick, N6KR
Eric Swartz, WA6HHQ

4ELECRAFT

Customer Service Information
Technical AssistanceIf you have difficulty with kit construction, operation, or
troubleshooting, we’re here to help. You may be able to save time by
first consulting our web site, www.elecraft.com, or by posting yourquestion on the Elecraft e-mail forum, elecraft@qth.net.
Telephone assistance is available from 9 A.M. to 5 P.M. Pacific time
(weekdays only) at 831-763-4211. You can also send e-mail tosupport@elecraft.com. Please use e-mail, rather than call, whenpossible since this gives us a written record of the details of yourproblem.

Repair Service
If necessary, you may return your completed kit to us for repair.
Contact Elecraft before mailing your kit to obtain the repair
shipping address, as well as information on repair fees. (Kits thathave been soldered using acid core solder, water-soluble flux solder,or other corrosive or conductive fluxes or solvents cannot be
accepted for repair–see Warranty.)
The following information should be provided to expedite repair:your name, address, and phone number; your e-mail address (ifapplicable); and a complete description of the problem.
Shipping: First, seal the unit in a plastic bag to protect the finish
from dust and abrasion. Use a sturdy packing carton with 3" or moreof foam or shredded paper on all sides. Seal the package withreinforced tape. (Neither Elecraft nor the carrier will accept liability
for damage due to improper packaging.) Cover the "to" address labelwith clear tape.

Elecraft’s 1-Year Limited WarrantyThis warranty is effectiv e as of the date of fi rst consum er purchase (or ir
shipped from factory, date product is shipped to customer). It covers both ourkits and fully assembled products. For kits, before requesting warranty service,
you should complete the assem bly, careful ly fol lowing al l i nstructions i n t hemanual.
Who is covered: This warranty covers the original owner of the Elecraft
product as disclosed to Elecraft at the time of order. Elecraft products
transferred by the purchaser to a third party, either by sale, gift or othermethod, who is not disclosed to Elecraft at the time of original order, are notcovered by this warranty. If the Elecraft product is being bought indirectly for athird party, the third party's name and address must be provided to Elecraft attime of order to insure warranty coverage.
What is covered: During the first year after date of purchase, Elecraft will
replace defective or missing parts free of charge (post-paid). We will also
correct any malfunction to kits or assembled units caused by defective partsand materials. Purchaser pays inbound shipping to Elecraft for warranty repair,
Elecraft will pay shipping to return the repaired equipment to you by UPS
ground service or equivalent to the continental USA and Canada. Alaska,
Hawaii and outside U.S. and Canada actual return shipping cost paid by owner.
What is not covered: This warranty does not cover correction of kit assembly
errors. It also does not cover misalignment; repair of damage caused by misuse,
negligence, or buider mdifications; or any performance malfunctions
involving non-Elecraft accessory equipment. The use of acid-core solder,water-soluble flux solder, or any corrosive or conductive flux or solvent willvoid this warranty in its entirety. Also not covered is reimbursement for loss ofuse, inconvenience, customer assembly or alignment time, or cost ofunauthorized service.
Limitation of incidental or consequential damages: This warranty does notextend to non-Elecraft equipment or com ponents used i n conjunction with our
products. Any such repair or replacem ent is the responsibility of the custom er.
Elecraft will n ot be liable for any special, indirect, incidental or consequential
damages, including but not limited to any loss of business or profits.

ELECRAFT

5

2. Specifications
Measurements were made using a 14-V supply and 50-ohm load.

Transmitter

GeneralSize (H x W x D)
CabinetOverall

2.2 x 5.2 x 5.6" (5.6 x 13 x 14 cm)
2.4 x 5.2 x 7.1" (6 x 13 x 18 cm)

Weight1.4 lbs. (0.6 kg), excluding options

Supply voltage

8.5 to 15 VDC

Current drain
Receive
Transmit

1

55 mA typ. (no signal)
700-900 mA typ. (5 W, 14 VDC)

Power output

0-5 watts or higher; spurious andharmonic content -40 dB @ 5 W

Load tolerance

2:1 or better SWR recommended;
will survive high-SWR operation

Sidetone pitch

400-800 Hz in 10 Hz steps

Internal keyer

8-50 WPM; Iambic modes A and B;
2 message buffers; auto-repeat

Receiver

Bands covered (MHz) 3.5, 7.0, 10.1, 14.0, 18.05, 21.0
(2 or 4 selected bands per module)

Sensitivity

Approx. 0.2 µV for 10 dB (S+N)/N

Frequency control

I.F.

4.915 MHz, single conversion

Selectivity

4-pole variable-bandwidth crystal
filter, approx. 200-800 Hz

Electronically-tuned 3 MHz VFO;
approx. 80 or 150 kHz range,
selected during assembly

VFO drift< 200 Hz per hour after 5-minutewarm-up at 25° C

Audio output

1 watt (peak) into 8-ohm load

RIT/XIT range

Approx. +/- 3 kHz1Int. speaker

8 ohms, high-efficiency

Display

3-digit LCD w/bargraph modes

Headphones
or ext. speaker

8 ohms or higher; stereo plug
(mono optional--see page 31,
second assembly step)

The RIT/XIT range can be easily modified; see page 55.

ELECRAFT

6

3. Preparation for Assembly
Overview of the K1
The K1 uses modular design for ease of assembly andtroubleshooting. The chassis is made up of five pieces (Figure 3-1),
any of which can be removed individually. The RF power amplifiertransistor uses the right side panel as a heat sink, so there is no
separate heat sink element. Each side panel includes a 10-32
threaded PEM nut as a mounting point for the KTS1 tilt stand.

There are three printed circuit boards (PCBs), as shown in
Figure 3-2: Front Panel board, Filter board, and RF board. Theseboards plug in together with no wiring, as explained in the next
section. K1 options, such as the KNB1 noise blanker, also plug indirectly. Appendix D shows photographs of each completed PC
board assembly.

Side
Panel

FilterTop Cover

Front
Panel
Front
Panel

RF

BottomCover(Right side panel
not shown)

Figure 3-2

Figure 3-1

ELECRAFT

7

Board-to-board Connectors
The circuit boards in the K1 plug in together using board-to-board connectors, which eliminates nearly all hand wiring. Gold-plated contacts
are used on these connectors for reliability and corrosion resistance.
Figure 3-3 shows a side view of the PC boards and board-to-board connectors. As can be seen in the drawing, the Front Panel board has aconnector J1 which mates with right-angle connector P1 on the RF board. The Filter board has three connectors, P1, P2 and P3, which matewith J6, J7 and J8 on the RF board.
These multi-pin connectors are difficult to remove once soldered in place. Refer to Figure 3-3 during assembly to make sure
you have each connector placed correctly before soldering. If you install a multi-pin connector incorrectly, clip all of the pins at
the body of the device first, remove all of the pins individually, and call us to request a new connector. You may damage pads
and traces by trying to remove such components intact.

Front Panel
Filter Board
P1,P2

P3

J6,J7

J1
P1

J8

RF Board
Figure 3-3

K1-2 (2-band version) and K1-4 (4-band version)
This manual covers all aspects of assembly for the two-band K1 (model K1-2). If you purchased a four-band K1 (model K1-4), you'll use theKFL1-4 assembly manual during assembly and alignment of the Filter board. You'll find instructions specific to the 4-band module at all
appropriate places in this Owner's manual.

ELECRAFT

8

Unpacking and Inventory
Handling Integrated Circuits and Transistors
This kit uses integrated circuits (ICs) and transistors thatcan be damaged by electrostatic discharge (ESD). Problems
caused by ESD can often be difficult to troubleshoot. To
avoid this:






Leave parts in their anti-static packaging until you install themUse an anti-static mat on your work bench
Use a soldering iron with a grounded tip
Ground yourself using a wrist strap with 1-Mohm series resistor
At minimum, touch an unpainted, grounded metal surface
before handling ESD-sensitive components

Inventory
We recommend that you do a complete inventory, using the parts
lists in Appendix A. Start with the K1 Packing Box Parts list,
which details the items you should find when you first open thebox. Additional parts lists are provided for components used in eachsubassembly. Component photographs are provided in most cases.

Identifying Resistors and RF Chokes
Resistor and RF choke values and color bands are provided in the
text. However, it's helpful to familiarize yourself with the color
code. The color-code chart, Figure 3-4, shows how to read the fourcolor bands on 5% resistors. For example, a 1,500 ohm (1.5 k) 5%
resistor has color bands BROWN, GREEN, RED and GOLD.
1% resistors are similar, but use five bands: three significant digits, amultiplier, and tolerance. The first four bands on a 1.5 k, 1%
resistor are BROWN, GREEN, BLACK, BROWN. The multipliervalue is 1 rather than 2 in the this case because of the third
significant digit. 1% resistors have color bands that are sometimes
hard to distinguish clearly; use an ohmmeter to identify them.

The markings on RF chokes reflect their value in microhenries(µH), using two significant digits and a multiplier. Example: a chokewith color bands RED, VIOLET, BLACK has value of 27 µH.

Color CodeTolerance(gold = 5%,
silver = 10%)Multiplier
Second DigitFirst Digit
Color
Digit
Black
0
Brown
1
Red
2
3
OrangeYellow
4
Green
5
Blue
6
Violet
7
Gray
8
White
9
Silver-Gold--

Multiplier
x1
x 10
x 100
x 1K
x 10K
x 100K
x 1M

Figure 3-4

x .01
x 0.1

ELECRAFT

9

Identifying Capacitors

Soldering and Desoldering

Small-value fixed capacitors are usually marked with one, two, or
three digits and no decimal point. If one or two digits are used, thatis the value in picofarads (pF). If there are three digits, the third
digit is a multiplier. For example, a capacitor marked "151" would
be 150 pF (15 with a multiplier of 101). Similarly, "330" would be
33 pF, and "102" would be 1000 pF (or .001 µF). Exceptions aredescribed specifically in the text and parts list.

Use adequate ventilation when soldering, and avoid
inhaling smoke or fumes. Always wash your hands after
handling solder, as lead residue is highly toxic.

Fixed capacitors with values of 1000 pF or higher often use a
decimal point in the value, such as .001, .047, or 2.2. This is thevalue in microfarads (µF). (1 µF is equal to 1,000,000 pF.)

Tools
The following specialized tools are supplied with the K1:


.050" (1.3 mm) and 5/64" (2 mm) Allen wrenches
Double-ended plastic alignment tool

In addition to the tools supplied, you will need these standard tools:










Temperature-controlled soldering iron, 700-800°F (370-430°C)
Fine-point soldering iron tip, approx. .05" (spade type)
Small-diameter, IC-grade solder (see Solder Recommendations)
Desoldering tools (wick, solder-sucker, etc.)
Needle-nose pliers
Small-point diagonal cutters, preferably flush-cutting
Small Phillips and flat-blade screwdrivers
DMM (digital multimeter; do not use an analog VOM)
Magnifying glass

We strongly recommend that you use a conductive wrist strap andanti-static mat during assembly. These items are available at very
low cost from Jameco, Mouser, and other electronics suppliers.

Solder Recommendations
We recommend small-diameter (.02 to .04") rosin-core solder,similar to Kester type 44. Solder with 2% silver is used by somebuilders and will work equally well. If you use a minimum of solder,
there will be no need to clean PC boards. The use of acid-coresolder, water-soluble flux solder, or any corrosive or conductive flux
or solvent is likely to damage components and/or PC boards.

Soldering
When applying solder, use the minimum amount required tosurround the component lead and make good contact with its
printed-circuit pad. You don't need a "fillet" (build-up) of solder.
To provide a good connection, the solder must flow onto both thecomponent lead and its PC board pad. To ensure that both will beheated at the same time, the tip of the iron should contact both thecomponent lead and the PC board pad before solder is applied.
Solder joints should be clean and shiny. If a joint appears dull or has
fine cracks, it is probably cold. Cold solder joints should be cleaned
and re-soldered. First, use solder wick (desoldering braid) to remove
the old solder. Then apply fresh solder. If you have many cold
solder joints, it probably indicates that your soldering irontemperature is too low, or that the tip or solder itself is defective.
New soldering iron tips must be tinned before they’re used. Allow
the iron to warm up completely, then apply solder and allow it tocoat the entire tip. After a few minutes, wipe off the excess solder.
Use a sponge for wiping the iron tip, and clean the sponge often.

ELECRAFT

10

Desoldering

Assembly Notes

The printed circuit boards used in the kit are double-sided, meaningthat they have circuitry on both sides. The component mounting
holes are plated-through to complete electrical connections
between the two sides.

Each step in the assembly process is accompanied by a check-box:

Removing components from double-sided boards can be difficult,since you must get all of the solder back out of the hole before alead can be removed. To do this, you'll need solder wick(desoldering braid) and/or a vacuum desoldering tool. It also takessome practice. A number of suggestions are provided below.
The best strategy for avoiding de-soldering is to place allcomponents properly the first time. Double-check values
and orientations, and avoid damaging parts via ESD.
When removing components:








Don't pull a lead or pin out of a hole unless the solder has been
removed, or you are applying heat. Otherwise, you can literally
pull out the plating on the plated-through hole.
Limit soldering iron contact to a few seconds at a time.
Use small-size solder-wick, about 0.1" or 2.5 mm wide. Use thewick on both the top and bottom pads when possible. This
helps get all of the solder out of the hole.
If you use a vacuum desoldering tool (solder sucker), use a large
unit. Small solder suckers are not very effective.
The safest way to remove ICs and other components with morethan 3 leads is to clip all of the pins at the body of the device
first, then remove all of the pins individually. You may damage
pads and traces by trying to remove such components intact.
Invest in a PC board vice with a heavy base if possible. This
makes parts removal easier because it frees up both hands.

If in doubt about a particular repair, ask for advice from Elecraft orfrom someone else with PCB repair experience.

This symbol is used to alert you to important information:i
Do not skip any steps. You may adversely affect both theperformance and appearance of the kit by using the wrong
assembly order.

Components
Sometimes we refer to components by their PC board and reference
designator. For example, "FP-Q1" refers to transistor Q1 on the
Front Panel board.
A few components in the kit are mounted on the bottom of PC
boards. Component outline symbols are provided on theappropriate side of the board, so it will always be clear which side aparticular component goes on. Bottom-mounted parts are also
identified on the schematics by this symbol:

Photographs
Before beginning assembly, you should review the photographs inAppendix D to get an idea of what the completed PC boards look
like. You'll also find front and back views of each PC board in theParts Placement Drawings, Appendix F.

ELECRAFT

11

4. Filter Board
This section applies only to the two-band K1 Filter board. If
you have a four-band K1, refer to the assembly instructionsin the KFL1-4 manual.
The Filter board determines the K1's bands of operation.
A photograph of the completed board appears in Appendix D.
Open the bag of components labeled KFL-2 andsort the parts into groups. Identify components using thephotographs in the Filter board parts list in Appendix A.
Locate the Filter printed circuit board (PCB), labeled "K1
FIL2" on one side.
With the top side of the PC board facing you (notch at thelower right), locate the position of resistor R1, along the frontedge. The label "R1" appears just left of the resistor’s outline.
Install a 100-ohm, 5% resistor (brown-black-brown) at R1,
with its first color band (brown) toward the left. Make sure it isseated flat on the board, then bend the leads outward at about a 45degree angle to hold it in place.
Solder R1 on the bottom of the board. Trim the leads as close
as possible to the solder joints.

iComponents may be soldered one at a time or in groups.
Leads can be trimmed either before or after soldering.

Install an 18-pin IC socket at U1, with the notched end of thesocket oriented towards the "K1 FIL2" label. Bend two leads of thesocket outward slightly to hold it in place while soldering. (U1 itself
will be installed in a later step.)i

In the following steps you'll install three relays (K1-K3).
Relay pins must not be bent, even after placement on the PC board,as this may cause unreliable mechanical operation.
Place relays K1-K3 on the top side of the board. One end ofeach relay has a heavy line printed across the top to indicate thepin 1 end. This end must be matched with the same end of therelay’s PC board outline. Do not solder the relays yet.
When all three relays have been placed on the board, lay a flat
object such as a book or piece of cardboard on top of the relays tokeep them in place, then flip the board over.
Solder only two pins (at opposite corners) on each relay, using
a minimum amount of solder. Limit soldering time to 2 or 3
seconds per pin. Do not bend or trim the leads.
Turn the board back over and verify that all of the relays arein the correct orientation and are seated flat on the board. To
check the orientation, refer to the Filter board drawing inAppendix F, at the bottom of the page.
Solder all of the remaining relay pins. Do not bend or trim theleads.

ELECRAFT

12

Install the capacitors listed below. The list shows thecapacitance value, followed by the labeling (in parentheses). Afterinstalling each capacitor, bend the leads outward at about a 45degree angle to hold it in place until it is soldered and trimmed.
__ C29, .001 (102)__ C30, .001 (102)

At this point you’ll need to choose whether to set up the VFO
for 80-kHz or 150-kHz coverage (approx.). The smaller range
covers the most-used portion of every band, provides smoothertuning, and is strongly recommended if you plan to upgrade to thefour-band module (KFL1-4), which has narrower band-pass filters.

__ C27, .047 (473)

Record your VFO range selection here for reference:
Place a bookmark at this page, and another at the
Per-Band Components table in Appendix A.
Locate the two bags of per-band components, which arelabeled by band, e.g. "40m" or "K1B40" (40 meters).
Under Reference Designators in the Per-Band Components
table, there are Band 1 and Band 2 columns. Fill in the blanks at
the top with your two bands (e.g., "40" and "20"). The lowerfrequency band should be designated as Band 1.
Using strips of paper, or labels with a light adhesive such as“post-its,” temporarily cover the band 2 reference designators
column. Similarly, cover all of the components columns except thecolumn associated with band 1. This is a very important stepthat will eliminate possible confusion during assembly.
Open the bag of components for band 1 only, setting theband 2 components aside for now.

i

The leads on small capacitors may be pre-formed so thatthe capacitor sits slightly above the board when inserted; this will
not affect performance. The leads are also somewhat fragile.
Install the capacitors for band 1, using the reference
designators and values from the appropriate columns in the parts
list. For example, if band 1 is 40 meters, install 390-pF capacitors
at C1 and C5, then 330 pF capacitors at C2 and C4, etc. Doublecheck each capacitor value as it is installed. Do not solder yet.
Solder all of the band 1 capacitors.

___ 80 kHz___ 150 kHz

Note: Two different crystals are supplied for 30 meters,
corresponding to two different lower band edges. Which one to use
depends on your selected VFO range (see below). In the following
steps you’ll select one of the two crystals when applicable.
Band
30 Meters

VFO Range
80 kHz150 kHz

Crystal18.10018.000Band Edge
10.10010.000If band 1 is 30 meters, select the appropriate crystal using thetable above. Save the other crystal for possible future use.
Install the band 1 crystal at X1 on the filter board (to the rightof X2), bending the leads to hold it in place. Make sure the crystal isseated correctly, then solder. Use a minimum amount of solder toavoid a short under the can.
Move the strips of paper or labels that you used earlier so thatthey cover the band 1 reference designators column, and all of thecomponents columns except the column associated with band 2.
Open the components bag for band 2. Install the band 2
capacitors, using the reference designators and values from theappropriate columns as before. (Example: if band 2 is 20 meters,
you'll install 180-pF capacitors at C6 and C10, etc.)
Locate the band 2 crystal and verify that it is the correct
frequency. If band 2 is 30 meters, select one of the two crystals
supplied (see table above). Install it at X2 and solder.

ELECRAFT

13

Cut two 3/4" (19 mm) bare wires (use component leads).
Referring to Figure 4-1, insert bare wires into the grounding
holes provided near X1 and X2. Fold each wire over the top of thecrystal and solder it on top. Keep soldering time below 5 seconds at
a time; if it takes longer, your iron may not be hot enough, or youriron tip may not be making good contact with the crystal can.
Solder and trim the wires on the bottom of the board.

At the left and right ends of the board you’ll find two shortjumper locations, each labeled with a ground symbol ( ). Use
component leads to make 3/4" (19 mm) U-shaped wires for eachjumper (Figure 4-2). Solder the jumpers on the bottom of the board,
with the top of the U-shape approx. 1/4" (6 mm) above the board.

Top side

X1

X2

Figure 4-2

Figure 4-1
Install the ceramic resonator, Z1, to the right of U1. (Theceramic resonator looks like a capacitor with three pins, and can beoriented in either direction.) Limit soldering time to 2 or 3 seconds
on each pin to avoid altering the oscillation frequency.
Locate the eight 1-µH slug-tuned inductors, and make surethey are all have a red stripe or are labeled "T1050".
Install the inductors at L1 through L8, pressing each one down
as far as it will go. They have five pins, plus ground tabs, and can
only be installed on the board one way. Solder the inductors.

Identifying Toroid Cores
Several toroidal inductors are used in the K1, including four on theFilter board. It is important to use the correct type of core. Thiscan be determined from the color and size.
The cores used on the Filter board are type T37-6. The T identifies
an iron-powder core. The number following the T specifies theoutside diameter in hundredths of an inch, in this case 0.37 inches(9.4 mm). The suffix (-6) refers to a specific mix of iron powder,which uses a particular color, in this case yellow.
Later in assembly you'll encounter ferrite cores, for example type
FT50-43. In this part number, FT identifies the core as ferrite, and
50 is the size (0.50", 12.5 mm). The suffix (-43) identifies the typeof ferrite used, although all ferrite cores are dark gray in color. All
ferrite cores used in the K1 are of the -43 type.

ELECRAFT

14

i

In the following steps you’ll install toroidal inductors L9L12 (type T37-6 cores). They must be wound as indicated in the
instructions, or the transceiver will not operate correctly. Use only
the number of turns specified. It is not necessary to attempt toprecisely match the inductances specified in the parts list.

Verify that the turns of L9 are not bunched together. They
should be evenly spaced, and should occupy about 80-90% of the
core.

Find the component outline for L9 on the Filter board.
Compare this component outline to Figure 4-3, which shows twoviews of a typical toroidal inductor. L9 will be mounted verticallyas shown at the right side of the drawing, with one wire exiting at
the core’s upper left, and the other at the lower right. There arepads on the PC board in these two locations.

The enamel wire supplied with the kit can be heat-stripped. One
way to do this is to place a small amount of solder (a "blob") on theend of your soldering iron, then insert the wire into the hot solder.
If the iron is hot enough, you should see the insulation vaporize
after 3 to 6 seconds. Another possibility is to burn the insulation
off by heating it with a small butane lighter for a few seconds, thenuse fine-grain sandpaper to remove the enamel residue. Avoid
scraping insulation off with a razor blade, as this may nick the wire.

Using the Per-Band Components parts table (Band 1),
determine the number of turns and wire length for L9 and L10.
To wind L9, cut the specified length of #26 red enamel-coatedwire, then "sew" the long end of the wire through the core. Eachpass through the core counts as one turn. The finished winding
should look similar to Figure 4-3, but with the number of turns
indicated in the parts list. Figure 4-3 shows 14 turns.

Stripping Toroid Leads

Strip the leads of L9, as explained above. You should remove
the enamel from the leads up to about 1/8" (3 mm) from the core
(Figure 4-3).
Tin L9's leads. The solder should appear clean and shiny. If it
looks dull or is not adhering very well to the bare lead, there is
probably some insulation remaining. Remove it as described above.
Install L9 vertically as shown by its component outline. Pull
the leads taut on the bottom of the board.
Solder the leads of L9. When soldering, make sure that thesolder binds well to the leads. If the lead appears to be an "island" ina small pool of solder, chances are it is not making good contact.
Wind and install L10 in the same manner as L9, using thesame number of turns. Install L10 vertically, to the right of L9.
Wind and install L11 and L12. Use the Per-Band Components
table (Band 2) to look up the wire length and number of turns.

Remove insulationi

Figure 4-3

Do not use adhesives or fixatives of any kind to secure L9L12 to the PC board. They will be adequately held to the board by
their leads alone.

ELECRAFT

15

i

The connectors to be installed in the following steps
must be positioned correctly to avoid intermittent or
unreliable operation.
Before attempting to install multi-pin connectors, review the
information on page 7.

Cut a 1" (25 mm) length of insulated hookup wire. Strip about
1/8" (3 mm) of insulation off of each end.
Install this wire between pins 2 and 10 of J2, in the upper righthand corner of the board (Figure 4-5). The pins on J2 are counted
from left to right and top to bottom as shown.

Install an 8-pin male connector (plug) at P1, but do not solder
yet. Figure 4-4 shows P1 as viewed from the left end of the Filter
board. The plastic part of the connector must be on the bottomside of the board, with the long end of the pins pointed down. The
short pins are inserted into the board.

1

2

9

10

J2

Figure 4-5i

Before handling U1 in the next step, touch an unpainted,
grounded metal surface.

P1
Figure 4-4
Solder just one of the middle pins of P1, on the top side.
Note: multi-pin connectors have plastic bodies that can melt if too
much heat is applied, causing the pins to be mis-positioned. Limit
soldering time for each pin to 2 to 3 seconds.

Straighten the leads of U1 (PIC16C620) as shown in Figure
4-6. The two rows of pins must be straight and parallel to eachother to establish the proper pin spacing. To straighten the pins,
rest one entire row of pins against a hard, flat surface. Press down
gently on the other row of pins and rock the IC forward to bend thepins into position as shown below.

FlaredExamine the placement of P1 closely. If it is tilted or is notflat against the board, re-heat the solder while pressing down on theconnector.

Straight

Once P1 is in the right position, solder the remaining pins. Do
not trim the leads.

Figure 4-6

Install P2 and P3 in the same manner as P1. Before soldering,verify that each connector is flat against the board and not tilted.

ELECRAFT

16
Insert U1 into its socket, with the notched or dimpled end of the
IC aligned with the notched end of the PC board outline. Figure 4-7
shows an 8-pin IC; U1 is similar but has 18 pins.) Press U1 down into
the socket as far as it will go.

Visual Inspection
Using the parts placement drawings in Appendix F, re-check theorientation of the relays (K1, K2, K3) and U1.

i

Notch
Pin 1

About 90% of all problems with kits are caused by poorlysoldered component leads. Such problems can be avoided by doing a
careful inspection of the board, preferably with a magnifying glass.

DimpleExamine the bottom of the PC board closely for cold solder joints,
solder bridges, and unsoldered components.

Pin 1
Figure 4-7
Note: IC pins are counted by going around the IC counter-clockwisefrom pin 1.
Examine U1 closely. If any pins are bent, remove the IC andstraighten them. (To remove U1 from its socket, pry it up gently oneach end using a small flat-blade screwdriver.)Locate the blank white area near U1. This area is provided forlabeling the Filter board with the two bands covered (e.g. "40, 20").
Use an indelible marker, dry transfers, or an adhesive label.

Uninstalled Components
All component locations on the Filter board should now be filled
except J1 and J2, which are provided for the automatic antenna tuner(KAT1). The KAT1 option should be installed only after the basic K1
kit has been completed and tested. At that time, the jumper you
installed between pins 2 and 10 of J2 will be removed. If you’rebuilding a 2-band Filter board that includes 80 meters, you’ll have a
10 µF electrolytic capacitor left over at this point. This will be
installed on the RF board at C78 in a later step.

Resistance Checks
Make the measurements listed below, touching the meter's (+)
and (-) leads to the indicated points. Measurements at relay K3 must
be made on the bottom side. Relay pins are numbered like ICs, withpin 1 identified by its round pad. The Filter board schematic (inAppendix B) may help you troubleshoot any incorrect readings.

i

The symbol > means greater than, and < means less than.
Your DMM may indicate infinite resistance (all digits flashing) for
readings that are listed as "> 100 k." (Do not use an analog VOM.)
Test Points (+, -)U1 pin 6, U1 pin 7
U1 pin 6, U1 pin 8
U1 pin 6, U1 pin 12
U1 pin 13, P2 pin 6
P1 pin 1, P1 pin 3
P1 pin 2, P1 pin 3
P1 pin 3, P1 pin 4
P1 pin 3, P1 pin 6
P2 pin 1, P2 pin 2P2 pin 7, P2 pin 8
K3 pin 2, K3 pin 9
K3 pin 4, K3 pin 7

Resistance
230-270 ohms
230-270 ohms
230-270 ohms
90-110 ohms
> 100 k> 100 k> 100 k> 100 k> 100 k> 100 k< 5 ohms< 5 ohms

ELECRAFT

17

5. Front Panel Board
The liquid-crystal display (LCD), switches, and other controls arelocated on the Front Panel board, as well as the microcontroller.
See Appendix D for photos of the completed assembly.
Open the bag labeled FRONT PANEL and sort the parts into
groups. Observe anti-static precautions with ICs and transistors.
Locate the front panel PC board, which is labeled "K1 FP"
along one edge. In the steps that follow, we will refer to the sidewith the switches and LCD (S1-S6 and DS1) as the top side.
Place the board in front of you with the bottom side up.
Locate the component outline for J1, below the large hole.
Install a 20-pin female connector (receptacle) at J1 as shownin Figure 5-1. Do not solder yet.

Solder one pin of J1 on the top side, near the middle of theconnector. If J1 is not seated flat against the PC board or is tilted,
re-heat the solder and press down on the connector.
Once you're sure that J1 is correctly installed, solder theremaining pins. Do not use an excessive amount of solder.
Locate the Switch Spacing Tool (made of PC board
material).
Position push-button switch S1 on the top side of the board asshown in Figure 5-2, using the switch spacing tool to set the switch
height. Make sure all four legs of the switch are centered in theirholes, then gently push the switch until it is resting flush against theswitch-spacing tool. (Caution: switch pins are fragile.) Do notsolder yet.

S1
Bottomside

Top side(with LCD)

J1

Figure 5-2
Figure 5-1

ELECRAFT

18

Top ofboard
1/16”

Figure 5-3
Figure 5-3 shows a side view of a switch that is properly mounted(spacing tool not shown). The leads of the switches will just be
visible on the bottom of the board. Proper switch height isimportant for maintaining an even appearance.
Once S1 is seated correctly, solder the leads on the bottom sideof the board. Leave the spacing tool in place while soldering.
Install S3, once again using the switch spacing tool to adjust
the switch height. When soldering S3, be careful not to contact theplastic body of J1 with the soldering iron.
Install switches S2, S4, S5, and S6 using the same technique.
Note: Switch caps will be installed later.
Install these parts on the top side of the board. Solder them on
the bottom side, using a minimum of solder.
__ R8, 22 (RED-RED-BLK)__ C4, .047 µF (473)

Trim the leads of R8 and C4 as close to the board as possible
so that they won't interfere with the 40-pin IC socket (next step).
Install the 40-pin IC socket at U1, on the bottom side of theboard. The board is labeled "SOCKET" at this location. Orient thesocket's notched end to the left (the pin 1 end). To hold the socketin place, bend pins 1 and 21 outward slightly; these two pins are
diagonally opposite. Solder only these two pins.

If the socket does not appear to be seated flat on the PC
board, reheat these two pins while pressing on the socket. If theleads of C4 hit the socket, trim them closer to the board.
Solder the remaining pins of U1. (U1 itself will be installed in
the socket in a later step.)
Install and solder the following components. When soldering
components near the push-button switches, be careful not to touch
the switches with the soldering iron.
Top side:__ R4 and __ R5, 10 k (BRN-BLK-ORG)__ R11, 100 k (BRN-BLK-YEL)

Bottom side:__ R6, 12.7 k, 1% (BRN-RED-VIO-RED)__ R7, 3.92 k, 1% (ORG-WHT-RED-BRN)__ R9, __ R10, and __ R19, 100 k (BRN-BLK-YEL)__ R13, 470 (YEL-VIO-BRN)__ R12, 2.7 k (RED-VIO-RED)__ R14 and __ R15, 1 k (BRN-BLK-RED)__ R16, 2.7 k (RED-VIO-RED)__ C5 and __ C6, .01 µF (103)Install capacitors C1 and C2 (82 pF), near U1.
Locate resistor network RP1. ("RP" means "resistor pack,"
another name for resistor networks.) One end of RP1 has a band or dot,
indicating pin 1. RP1 should be labeled 77083102, 83C102, or
8A3102G. If the labeling differs, verify the resistance. You shouldmeasure about 1.0 k between each pair of adjacent pins.
Install RP1 on the bottom side of the board. The end with adot or bar should be oriented towards pin 1 of the PCB outline.
When soldering RP1, keep the iron tip away from S4 and S5.
Install and solder the two 82-µH RF chokes, RFC1 and RFC2
(GRAY-RED-BLK).

ELECRAFT

19i

Before handling ICs and transistors in the following steps,
touch an unpainted, grounded metal surface.
Locate transistor Q1 (type 2N4124), which has a small, 3-lead
TO-92 package. Q1 and other TO-92 devices may have either of
the two shapes shown in Figure 5-4. The right-hand illustrationshows a "modified TO-92" package, which may be labeled on either
the front or back side. The large flat side of each device will bealigned with the flat side of its component outline.

Locate U4, a 78L06 voltage regulator, which has a TO-92
package similar to Q1. Install U4 below the large hole.

i

Touch an unpainted, grounded metal surface before
handling the 2N7000 transistor in the next two steps.
Locate the component outline for Q2 (2N7000) on the top
side of the board near the rectangular hole. Q2's outline has thethree pins side-by-side, not in a triangular pattern. Pre-form theleads of Q2 to match this hole pattern, so that it can be mountedvery close to the PC board with little excess lead length.
Install Q2. Make sure the top of Q2's body is no morethan 0.25" (6 mm) above the board when seated. Solder Q2.
Install the 8-pin ICs, U2 (MAX518), U3 (24LC04), and U5(LM358) on the bottom side. Orient the notched or dimpled end ofeach IC with the notched end of its component outline (see Figure4-7). Bend two leads outward slightly on the opposite side of theboard to hold the devices in place, but do not solder yet.

Figure 5-4

Turn to Appendix F (parts placement drawings) to verify thatyou have the ICs installed in the proper locations, then solder.
Limit soldering time to 2 to 3 seconds on each lead.

Install Q1 on the bottom side of the board, to the right of thelarge hole. Align Q1 as shown above. The transistor should be
mounted about 1/8" (3 mm) above the board; don’t force it down
too far or you may break the leads. Bend the leads outward slightly
to hold Q1 in place, then solder and trim the leads.

On the top side of the board at the left end you’ll find a shortjumper location, labeled with a ground symbol ( ). Install a 3/4"
(19 mm) U-shaped wire here, as you did earlier on the Filter board.

i

The potentiometers to be installed in the next step can bedamaged if you push on their plastic shafts. When seating a
potentiometer, press down only on the metal frame.
Install the two 10-k potentiometers at R2 and R3 (on the top
side of the board). They must be pressed downward until the metalframe is fully contacting the PC board on both sides. Do not use
excessive heat when soldering.

ELECRAFT

20

Open the bag labeled MISCELLANEOUS and empty thecontents into a shallow box or pan. This will prevent loss of any of
the small hardware while allowing you to locate items as needed.

Top SideiFive sizes of 4-40 screws are used. All are black anodized
except the 1/4" and 3/8" pan heads (see Figure 5-5). The length offlat-head screw is measured from the top of the head.

Pan-head, 1/4” (6 mm)
Figure 5-6

Pan-head, 3/8” (9.5 mm)

Install crystal X1, near C1 and C2 on the bottom of the board.

Pan-head, 3/16” (4.8 mm)

To the right of X1 you'll find a ground pad for the crystal can.
Use a discarded component lead to make the grounding wire, as
shown in Figure 4-1 (page 13).

Flat-head, 3/16” (4.8 mm)

Locate LEDs D1 and D2, which are identical in size but havedifferent-colored bodies. D1 has a clear diffuse body, while D2 has ayellow tint. Near the point where the leads exit the body, you'll finda flat side in the plastic, which identifies the cathode lead.

Flat-head, 5/16” (8 mm)
Figure 5-5
Identify all of the 4-40 screws and sort them into groups.
Install a 3/16" (4.8 mm) diameter x 1/4" (6.4 mm) long roundstandoff on the top of the board (Figure 5-6). The hole for thisstandoff is just below the large hole. Use two #4 split lock washers
and a 1/4" (6 mm) pan-head screw (not black anodized) as shown.
Insert the lock washers between the standoff and PC board.

Install D1 (clear diffuse body) on the top side of the board,
with its flat side aligned with the flat side of the component
outline. (This is the side nearest the square pad.) Position D1 about
1/16" (1.5 mm) above the board. You can use the switch-spacing
tool, a toothpick, or short length of insulated hookup wire to
maintain the proper spacing while soldering.
Verify the orientation of D1's flat side, then solder.
Install and solder D2 using the same method.

ELECRAFT

21

Inspect the solder side of U1's socket on the top side of the board.
Make sure all pins are soldered, with no cold solder joints.
Using a DMM, check every pair of adjacent pads on U1 on the
top side of the board (pins 1-20 and 21-40). The resistance between
pads should be over 1000 ohms (1 k) in all cases, and may read infinite
on your DMM (often indicated by a flashing display).

i

Caution: the LCD (DS1) and its pins are fragile.

Remove the LCD from its packing materials, being careful not tobend the pins. As shown in Figure 5-8, the pin 1 end of the LCD glass
has a very slight bump, along with a break in the black border. Thisend will be oriented towards the pin 1 end of DS1's component
outline.

i

24

Before handling U1 in the next step, touch an unpainted,
grounded metal surface.
Straighten the pins of the microcontroller, U1. You can hold the
IC body at the ends as you re-form each row of pins.
Insert U1 into its socket, with the notched end oriented towards
the pin 1 end of the component outline.
Look at both rows of pins on U1 closely. If any pins are bent,
carefully remove the IC by prying at both ends using a small flat-blade
screwdriver. Straighten the pins using long-nose pliers.
NOTE: If you purchased the K1 LCD Backlight Kit and are going toinstall it into your K1 now, refer to the instructions for adding thebacklight, then go directly to Visual Inspection on the next page.

Locate the black neoprene LCD spacer (MISC. bag), which is 1/2
x 1/2 square and 3/16" thick (12 x 12 x 5 mm). Remove the adhesive
backing from one side and position the spacer as shown in Figure 5-7.
It must be mounted flat against the PC board, centered between thetwo rows of pins on U1's socket.

SpacerFigure 5-7

13

Bump
DS1
1

12

Figure 5-8
Remove the adhesive backing from top side of the LCD spacer.
Install the LCD at DS1, oriented as shown above. Make sure thatall 24 pins are inserted into their holes, then press down gently on the
LCD to secure it to the LCD spacer's adhesive surface. The LCD pins
may not extend all the way through the holes. The surface of the LCD
must be parallel to the PC board.
Once the LCD is positioned correctly, solder all pins.

ELECRAFT

22

Visual Inspection
Type 1

Using the parts placement drawings in Appendix F, re-checkthe orientation of the LEDs (D1 and D2), LCD (DS1), and all ICs.

Type 2

Examine both sides of the PC board closely for solder bridges,
cold solder joints, or unsoldered components.
CCW

Resistance Checks
CW

Set both potentiometers to their mid-points.

Resistance> 100 k> 100 k> 100 k> 100 k90-200 k> 100 k< 50 k
15-18 k> 100 kFront Panel Final Assembly
Cut three 1.25" (32 mm) lengths of hookup wire. Remove 1/4"
(6 mm) of insulation from both ends of each wire.
Locate the 10-turn potentiometer, R1. Look closely at
Figure 5-9, which shows the positions of the three lugs. The lugs
may be labeled 1, 2, and 3, or S, CW, and CCW. 10-turnpotentiometer labeling can be confusing, so use the drawing to
identify the lugs. Your potentiometer may be either of the two
types shown.

23
1 2 3 R1

The resistance measurements shown below can all be madefrom the top side of the board. The (-) lead of your DMM should beconnected to the ground jumper ( ) at the left side of the board.
Test Points (+)
DS1 (LCD) pins 1-24
J1 pin 6
J1 pin 7
J1 pin 8
J1 pin 10
J1 pin 12
J1 pin 15
J1 pin 16
J1 pin 19

1S

1 2 3 R1

Figure 5-9
Attach the prepared wires to the three lugs Each wire should be
wrapped around its lug, leaving the other end free. (Do not solder
yet.)
R1’s plastic body can be damaged if you apply too much heatto the lugs. Solder the three lugs, limiting soldering time to about
two seconds each.
Insert R1 through the large round hole in the Front Panelboard, rotating it into approximately the position indicated above.
Make sure that none of the lugs are touching the PC board.
Near the large hole in the board, you'll find three pads for R1's
leads (labeled 1, 2, and 3). Referring to Figure 5-9, insert thepotentiometer's wires into their corresponding holes. Do notsolder yet.

iCaution: If the leads of R1 are not connected to thecorrect pads, the potentiometer is very likely to be damaged.
Re-check the connections, then solder R1's leads on the top
side of the board. Avoid touching nearby parts with the iron.

ELECRAFT

23

Install caps on switches S1 through S6. S3's cap is square, while
the others are rectangular, as shown in Figure 5-10. The caps are
installed by pressing them onto the switch plungers.

After removing any masking tape, turn the front panel faceup, with the Elecraft logo at the top.
Position the clear plastic LCD bezel over the large LCD
opening, then secure it with four 2-56 screws (stainless steel) as
shown in Figure 5-11. Tighten the 2-56 screws only the amountneeded to hold the bezel to the front panel. Over-tightening may
crack the bezel or strip the threaded holes in the panel.

Figure 5-10

2-56 Screw (4)i

The LCD's glass surface is protected by a very thin,
nearly invisible piece of protective film. In the following
step, be very careful to remove only the thin film, not the
LCD's glass top. Do not use any type of metallic tool.
Hold the Front Panel PC board assembly under a strong light sothat you can see the surface of the LCD glass clearly. Using afingernail, rub one corner of the LCD's glass top to loosen theprotective film, then peel it off.
Locate the front panel chassis piece. Place it on a soft clothto protect the finish and labeling.
Some holes in the front panel are masked on the inside surface
during painting. If masking tape (usually green in color) is stillpresent, you'll need to remove it. To remove masking tape:

Use a blunt instrument such as a ball-point pen to push on thetape through a hole until the tape begins to lift away.
Peel the tape off, using a sharp tool if necessary. Be careful not
to scratch the outer surface of the panel.

LCD Bezel

Figure 5-11

Remove all hardware from the shaft of the 10-turnpotentiometer (R1). It will be re-attached in a later step.
Locate the 0.75" (19 mm) diameter nylon washer. Place thiswasher over R1's threaded bushing.

ELECRAFT

24

Insert the Front Panel PC board assembly into the front panel(Figure 5-12). The push-button switch caps should protrude slightly.

i

The Allen wrenches are located in a small bag with the
MISCELLANEOUS items. These wrenches may have been oiled
during manufacturing. Remove the wrenches and wipe off the oil, if
any, then discard the bag.
Use the larger Allen wrench (5/64" [2 mm]) to tighten the two
set screws on the large knob.
Set the AF GAIN and RIT/XIT potentiometers to midway intheir rotation, and place a small knob on each. Do not push down
hard on the knobs, as this may damage the potentiometers.
Tighten each knob's two set screws using the smaller Allen
wrench (.050" [1.3 mm]). Align the pointers per panel labeling.

Figure 5-12

The 1/4" (6.4 mm) standoff on the PC board should now be
visible through the countersunk panel hole just below R1. Secure thepanel to the standoff with a 3/16" (4.8 mm) flat-head screw.

i

Caution: The 10-turn potentiometer may have aplastic bushing. In the following step, do not over-tighten
the nut or you may strip the threads.
Use the nut and lock washer supplied with R1 to secure it to
the front panel. It should be just tight enough to keep R1 fromrotating.
Place the large knob on R1's shaft. Push the knob on until itjust touches the bushing. If the knob does not spin freely, move itout slightly. If the shaft or knob appears to be tilted, the large
nylon washer may not be positioned correctly (behind the panel).

i

At this point in the assembly, the push-button switches
may not all protrude an equal distance. The switch height will
become equalized once the front panel assembly is mated to the RF
board in a later step.

i

When you rotate the VFO knob, you may hear a faintsound produced by the wiper of the 10-turn potentiometer as it
moves across its resistance element. This is normal.

Uninstalled Components
All component locations should now be filled.

ELECRAFT

25

6. RF Board, Part I
In Part I, the VFO (variable-frequency oscillator) and receiversections will be assembled.
Open the bag labeled RF and sort the components into groups.
Observe anti-static precautions when handling transistors and ICs.

Locate the RF board and orient it as shown in Figure 6-1. Thisillustration shows the major areas of the board. Receiver and VFO
circuits occupy the front half; transmitter and T-R switch stages use
the rear half. The Filter board plugs into J6, J7, and J8.
Turn the board over. (Figure 6-2 shows the bottom side.)
Four 2-D fasteners will be attached to the RF board at the indicatedlocations to secure it to the chassis panels.

J8
T-R Switch
and Transmitter
J6J7

2-D Fastener

VFO
Receiver
AF AmpFigure 6-1
Figure 6-2

ELECRAFT

26

Locate a 2-D fastener and hold it vertically (Figure 6-3a).
Looking at a side with two holes, note that the holes are offset
from the center. The PC board outlines for the 2-D fasteners havea matching offset, which will aid in installing them in the next step.

i

In the steps that follow you’ll install the connectors thatmate with the Filter and Front Panel boards. These connectors
must be installed properly to ensure reliable mechanical connection.
They are difficult to remove once installed, so follow all
instructions carefully. Review Figure 3-3 before proceeding.
Install an 8-pin female connector at J6, on the top side of the
RF board. It must be flush with the board and not tilted (Figure 6-4).
Solder just one pin near the center of J6.

Holes offset
from center

J6

(a)

(b)
Figure 6-3

Install 2-D fasteners at the four locations indicated in Figure
6-2, on the bottom of the RF board. Secure each fastener from the
top side of the board with 3/16" (4.8 mm) pan-head screws and #4
split lock washers (Figure 6-3b).
Make sure that the 2-D fasteners line up with the edges of the
PC board and do not hang over. If they hang over or do not match
their component outlines, they are installed backwards.
Install relay K1, near the center of the board. Make sure thepin 1 end (with the heavy line) is oriented as indicated by K1’s
component outline. Do not bend or trim the relay leads.

Figure 6-4
If J6 does not appear to be completely flush with the board, or
it is tilted, re-heat the soldered pin and press down. Do not solder
the remaining pins yet.
Install J7 and J8 in the same manner as J6, soldering just one
pin in each case.
The Filter board can now be used to check for proper
installation of the three 8-pin connectors. Place the Filter board
above the connectors (do not plug it in). Verify that all pins of P1,
2, and 3 on the Filter board align with the corresponding holes of
J6, 7 and 8 on the RF board.
Remove the Filter board. Solder all remaining pins of J6, 7,
and 8 on the bottom of the RF board.

ELECRAFT

27

Position 20-pin male right-angle connector P1 on the bottomof the RF board (Figure 6-5), but do not solder yet. Review Figure
3-3 for correct placement. The short ends of the bent pins areinserted into the holes, and the long ends are parallel to the board.

Top of board
Front edge

Install the resistors listed below. R23 is at the left-front edge.
__ R23, 1.5 Ω (BRN-GRN-GOLD) ⇒ __ R7, 680 (BLUE_GRAY-BRN)__ R21, 2.7 k (RED-VIO-RED)__ R13, 2.2 M (RED-RED-GRN)__ R2, 100 k (BRN-BLK-YEL)__ R16, 75 (VIO-GRN-BLK)__ R17, 120 (BRN-RED-BRN)__ R18, 75 (VIO-GRN-BLK)__ R14, 2.7 k (RED-VIO-RED)__ R1, 1.8 k (BRN-GRAY-RED)
These resistors start on the left edge of the board near J6:

P1
Figure 6-5
Solder just the two end pins of P1.
Make sure that the front-panel assembly can be plugged into
P1 as shown in Figure 3-3. Then unplug the front panel assembly.
Look closely at P1 to make sure that its plastic support ispressed down as far as it will go, and that the pins are parallel to theboard. If not, re-heat the soldered ends while pressing it into place.
Once it is seated properly, solder the remaining pins.

i

In the steps that follow, you'll be installing larger groups ofcomponents. When working from a long list, install all of the items
on one line before moving on to the next. Arrows (⇒) appear in
the list to remind you of this order. In general, assembly proceedsfrom left to right across the board.
Note: All components mounted in the T-R switch and transmitterareas must be kept as low-profile as possible since the Filter board
will be plugged in directly above.

__ R19, 39 k (ORG-WHT-ORG)__ R9, 2.7 k (RED-VIO-RED)⇒ __ R20, 20 k (RED-BLK-ORG)__ R26, 1.8 k (BRN-GRAY-RED)__ R34, 100 k (BRN-BLK_YEL)(at the back-right edge near J8)

The following capacitors are all of the disc or monolithic
type. Start with C26, which is on the left edge close to J6.
Note: C65 (22 pF) may be labeled "220J" (see top of page 9).
__ C26, 39 (39)⇒__ C41, .047 (473)__ C25, .01 (103)__ C6, .01 (103)__ C18, .01 (103)__ C64, .01 (103)__ C32, .047 (473)__ C27, 39 (39)⇒__ C30, .047 (473)__ C7, 39 (39)__ C69, 220 (221)__ C74, .01 (103)__ C68, 0.1 (104)__ C42, 220 (221)__ C40, .01 (103)__ C4, .01 (103)__ C72, .01 (103)__ C73, 0.1 (104)__ C17, .01 (103)__ C70, 0.1 (104)__ C75, .01 (103)__ C61, .047 (473)__ C66, .01 (103)__ C39, 220 (221)__ C36, .01 (103)__ C71, 0.1 (104)__ C63, 330 (331)__ C24, .047 (473)__ C21, .01 (103)__ C37, .01 (103)__ C34, 0.1 (104)__ C23, .01 (103)__ C65, 22 (22, 220J)__ C19, .001 (102)__ C22, .001 (102)__ C38, 220 (221)__ C28 and __ C29, .001 (102)__ C49 and __ C48, .01 (103)__ C45, .01 (103)(back-left corner of the board)(back-right corner)(near J4, which is on the back edge)

1200-pF polystyrene capacitor C11 (labeled “1200J”) has
axial leads, like a resistor. Note: the kit also includes a 120 pF
polystyrene ("120J"). Install C11 in the VFO area of the board,near J6. Limit soldering time to 2-3 seconds.

ELECRAFT

28

Install the resistor networks listed below, checking the partnumbers carefully before installation. Orient the black dot or bar oneach network towards pin 1 of its component outline.
__ RP3, 47 k, 10 pins (10A3473G, 103C104, or 770103473)__ RP1, 100 k, 8 pins (8A3104G, 83C104, or 77083104)__ RP2, 100 k, 8 pins (8A3104G, 83C104, or 77083104)__ RP6, 27 k, 6 pins (6A3273G, 63C273, 4306R-102 LF273 or 77063273)__ RP4, 3.9 k, 6 pins (6A3392G, 63C392, 94163392P or 77063392)__ RP5, 3.9 k, 6 pins (6A3392G, 63C392, 4163392 or 77063392)

Install a 33-µH RF choke (ORG-ORG-BLK) at RFC1, near thefront edge of the board. (Orange bands may appear to be brown.)
Install a 100-µH RF choke (BRN-BLK-BRN) at RFC4, in thetransmit area of the board.
The ceramic trimmer capacitors (C13 and C20) have one sidethat is flattened. This side must be oriented towards the flattenedside of the component outline. Install C20 near the front edge ofthe board, and C13 in the back-left corner.
Sort the diodes into groups for identification purposes. You
should have two types of small glass-bodied diodes: 1N5711, and1N4148. The 1N4753 zener diode may also be glass, and is larger.
If necessary, use a magnifying glass to read the labels.

Identify the two types of black, axial-lead diodes: 1N4007 andSB530. The 1N4007 is the smaller of the two.
Install the SB530 diode at D16, near the back edge of theboard.
Install 1N4007 diodes at D11 and D10, to the left of D16.
Install a 1N4007 diode at D5, near J7.
The varactor diodes have a small plastic package, like a TO-92
transistor, but with only two leads. Sort the varactor diodes into
two types: MV209 (quantity 1) and 1SV149 or V149SL (quantity 4).
Install the varactor diodes listed below. The flat side of each
diode must match the flat side of its PC board outline. Bend theleads slightly on the bottom to hold the diodes in place.
__ D4, MV209(in the VFO area)

Note: The 1SV149 diodes may have a third lead in the center, cut off near the
body. Mount them slightly above the board to avoid letting this lead shortthe two pads together.
__ D3, 1SV149__ D6, __ D7, __ D8, 1SV149(in the VFO area)(right-front corner)ii

Diodes with long axial leads (such as the types mentioned
above) must be installed with the banded end (cathode) oriented
towards the banded end of their component outlines. If a diode has
more than one band, the widest band indicates the cathode end.
Install 1N4148 diodes at D17 and D1, observing the proper
orientation as explained above. Do not solder yet. D17 and D1 areboth near RP2, in the VFO area.
Install 1N5711 diodes at D2 and D15, but do not solder yet. D2
is in the VFO area. D15 is in the back-right corner near J8.
Re-check the orientation of the diodes, then solder.

TO-92 package may have either of the package types
shown in Figure 5-4 (page 19). Orient the large flat side of the
package with the flat side of the component outline. Verify thepart numbers using a magnifying glass if necessary.
Install the TO-92 package transistors listed below, starting with
Q9 in the VFO area. Observe anti-static precautions.
__ Q9, 2N3906 ⇒__ Q10, 2N7000__ Q3, 2N4124__ Q8, J309⇒__ Q2, MPSA14__ Q11, J309__ Q1, 2N7000

ELECRAFT

29

Push the black keycap onto S1’s plunger until it snaps.

iTransistor Q4 (ZVN4424) is labeled on the back (the sidewith smaller area), which is different from most TO-92 devices.
The labeled side of Q4 must face the power switch, S1.
Install Q4 (ZVN4424A) in the back-right corner near S1.

Install the DC input jack, J4, at the back edge. The 3 leads on
the jack must be lined up with the slot-shaped holes in thecomponent outline. If the holes are a tight fit, press firmly until
the connector snaps into position, flat against the board.

Install U6 (78L06) near the left edge of the VFO area.
Install the 8-pin ICs listed below. Orient the notched or
dimpled end of each IC with the notched end of its component
outline (see Figure 4-7). Make sure the part numbers on the ICs
match the numbers on the component outlines.
__ U4, LM380N-8 (do not confuse with U3--check part numbers carefully)__ U3, LM386N-1__ U2, __ U7, and __ U1, SA602AN (alternates: NE602, SA612, NE612)

Install the following components on the bottom of the board,soldering them on the top side. Note: R3 is easier to solder on thebottom. In this case, pre-trim the leads to the correct length.
__ R3, 8.25 k, 1% (GRAY-RED-GRN-BRN)(see note above)__ R15, 10 ohms, 5% (BRN-BLK-BLK)__ R5 and __ R6, 2.7 k (RED-VIO-RED)__ R27, 1.8 k (BRN-GRY-RED)__ D12, 1N4007 (black body)__ RFC6 and __ RFC7, 100 µH (BRN-BLK-BRN)__ C5, 3300 pF polystyrene (3300J)__ C12, 1200 pF polystyrene (1200J)

Install C8 (82 pF) on the bottom of the board, near P1.
Before soldering, fold it down against the board, towards the back.
On the top and bottom sides of the board near J7 you’ll findshort jumpers ( ). Install U-shaped wires at both locations.
Locate the DC power switch, S1. Install S1 near the back of
the board, with the plunger facing the back edge. Make sure S1 ispressed firmly onto the board, and that it is not tilted.

Visual Inspection
Verify correct orientation (banded end) of each diode installed
so far, using the parts placement drawing (Appendix F).
Examine both sides of the PC board closely for solder bridges,
cold solder joints, or unsoldered components.

Resistance Checks
Make the resistance checks listed below, with your DMM's (-)
lead connected to the ground jumper ( ) near J7. The
measurements on P1 (the 20-pin right-angle connector) should betaken from the bottom side of the board.
Test Points (+)
P1 pin 6
P1 pin 7
P1 pin 8
P1 pin 12
P1 pin 14
P1 pin 15
P1 pin 16
P1 pin 17
U3 pin 3U3 pin 5U4 pin 3U4 pin 6U4 pin 7

Resistance> 100 k> 100 k> 100 k> 10 k> 100 k> 100 ohms
>1k
>1k
< 200 k> 10 k> 50 k> 10 k>1k

ELECRAFT

30

i

Electrolytic capacitors are mounted vertically, so their PC
board outlines are circular. The (+) lead must be installed in the holemarked with a "+" symbol. The (+) lead is usually longer than the (–)
lead, and the (–) lead is identified by a black stripe (Figure 6-6).

-+

Figure 6-6
Install the electrolytic capacitors listed below. They must be
seated as close to the PC board as possible to avoid interfering with
option modules that you may install later. Note: The 10-µF capacitors
are of the low-profile type, so they may be smaller than the 2.2-µF
capacitors.
__ C33, __ C59, and __ C35, 10 µF (see note above)__ C54, __ C31, and __ C67, 2.2 µF__ C9, __ C10, and __ C53, 220 µF

8-volt regulator U5 (LM2930T-8) is a TO-220 package device
with 3 leads (see photo in parts list). Mount U5 vertically at the backedge of the PC board (Figure 6-7). Only the wide part of the leads
should be above the board. The hole in the tab of U5 will not be used
for mounting, so positioning is not critical.

Locate the component outline for RFC8, on the bottom of the RF
board in the transmitter area. Install a short wire jumper at RFC8,
formed from a component lead or solid hookup wire.
Note: an RF choke may be supplied with the 80-meter band kit (2band Filter board only) for use at RFC8. This RF choke can beinstalled at any time, and will have no effect on K1 alignment or
testing on any band. Its function is to improve stability on 80 meterswhen the K1 is used with poorly-matched loads or an ATU.

DC Voltage Checks
Set power switch S1 to its OFF position, with the plunger out(extended toward the back).
Connect a 12 to 14-V DC power supply or battery to J4. If yourpower source does not already have a plug that mates with J4, use thesupplied mating plug and prepare a suitable power cable. The center
lead of the plug is positive (+).
Turn on S1. If you see or smell smoke, or a component feels
hot to the touch, disconnect the power source immediately. Locate
the source of trouble before proceeding.
Using your DMM's DC voltage setting, make the DC voltage
checks listed below. The (-) lead of your DMM should be connected to
one of the ground jumpers.

i

Be careful not to short adjacent pins of ICs with the DMM
probe (use only a fine-point probe).

Figure 6-7

Test Point (+)
P1 pin 15
P1 pin 16
U3 pin 5U3 pin 6

DC Voltage
5.8-6.2(supply - 0.3 V)
3.8-4.2
7.6-8.7

ELECRAFT

31
Turn the K1 off and disconnect the power supply.
Install the headphone jack, J2, on the small board extension near
the front-left corner. The pins on J2 are not very long, so they will benearly flush with the bottom of the board. Solder the pin closest to thefront edge first (ground), then verify that the jack is seated flat on its
plastic nubs before soldering the other pins.
Mono Headphones: If you plan to use only a mono plug at J2, cut thetrace marked "cut = mono" on the bottom of the board, under J2.
(You'll lose the sound on one side of stereo headphones.)
Install the key jack, J3, at the back-left corner. Before soldering,
make sure that the jack is aligned with its PC board outline.
Install the antenna jack, J5 (BNC), in the back-right corner.
Solder one of the large ground mounting pins first. If J5 then appears
to be tilted or twisted, reheat this ground pin while pushing J5 down
onto the board. Once it is seated properly, solder the remaining pins.
The internal speaker connector, P2, is a 2-pin connector with alocking tab. Orient P2 as shown by its PC board outline, near thefront-right corner of the board, with the locking tab facing the front.
P2 must be seated flat against the board before soldering.
Install crystal X5, near the front edge of the board. Make sure itis flat against the board and not tilted before soldering. (The leads canbe bent to hold it in place.)
Install X6 near the back-left corner.
Install X1-X4 at the front-right corner.
Ground the cases of all six crystals, using the near-by groundpads. Use discarded component leads as before. Limit soldering time
to 4-5 seconds to avoid overheating the crystals.

Install R39 (1.8 k, BRN-GRAY-RED) on the bottom of the board
near crystal X6.
In the back right corner of the board near the antenna jack (J5),
install P3, a 3-pin male connector. The long end of P3's pins face up.
Install the two-pin shorting jumper across pins 1 and 2 of P3 (thetwo terminals closest to J5).
On the bottom of the board, install R4 (5.6 k, GRN-BLUE-RED).
Locate the miniature slide switch, S2. Install S2 on the bottom of
the board, with the switch pressed down onto the board as far as it willgo. (If it isn't pressed all the way down, the actuator might hit thebottom panel.) Limit soldering time on each of S2's pins to 2 seconds
to avoid melting the plastic body.
Set S2's actuator to the "OPER" (operate) position.
Locate the component outline for RF choke RFC9, on the bottomof the board between the pins of relay K1. Flush-trim the four pins of
K1 closest to RFC9.
Form the leads of RFC9 (15 µH, BRN-GRN-BLK) to fit between
the indicated pads. Install RFC9 and position its leads so that they
don't contact any adjacent pads of K1. Solder and trim RFC9's leads
from the top side of the board.

ELECRAFT

32

Locate the dark gray (ferrite) toroid cores. You should havefour smaller cores (type FT37-43) and one larger core (FT50-43).
The three inductors to be wound in the following steps, L2, T1, andT2, all use the smaller ferrite cores.

Install T1 flat against the board, between U1 and U2. Insert
the leads into its numbered holes as shown by the component
outline. Pull the leads taut on the bottom, then solder and trim.
1, GRN2, GRN

3, REDi4, RED

Review the toroid winding and lead preparation instructions
if necessary (page 14).
Wind L2 using 16 turns of red enamel wire (11 inches, 28 cm).
L2 should appear similar to Figure 4-3, on page 14 (the figure
shows 14 turns rather than 16). Recall that each pass of the wire
through the core counts as one turn.

4, RED

2, GRN

Prepare L2's leads as before (page 14). Remove the insulation
to within about 1/8" (3 mm) of the core, then tin the leads.

3, RED(b) T2(a) T1
Install L2 vertically, at the back edge of the RF board between
the on-off switch (S1) and the antenna jack (J5).

i

T1 is a toroidal transformer, with two numbered windings.
These numbers are printed next to each pad on the PC board. T1's
windings are 1-2 and 3-4.
T1 is wound on an FT37-43 ferrite core (dark gray) and has
windings similar to those shown in Figure 6-8a. Wind the 3-4
winding first, using 20 turns of red enamel wire (13", 33 cm). Thiswinding should occupy 80 to 90% of the core. Note: the drawing
shows only 14 turns.
Wind the 1-2 winding on top of the 3-4 winding, using 4 turnsof green enamel wire (6", 16 cm). These turns should be woundtightly, and will overlap the turns of the first winding. (The drawing
shows the turns interleaved, for clarity, but this is not required.)
Strip and tin all four of T1's leads carefully.

1, GRN

Figure 6-8
T2 is wound on the same core type as T1. Start with the
3–4 winding, which uses 20 turns of red enamel wire (13", 33 cm).
The 1-2 winding uses 5 turns of green enamel wire (6", 16 cm).
Strip and tin T2's leads.
Install T2 flat against the board, to the right of U2. Pull theleads taut, then solder.
Using your DMM, check for continuity between the pads of
L2. If the DMM doesn't indicate a short (< 5 ohms), you may nothave fully removed the insulation from one or both leads. Since theinsulation can be heat-stripped, you can usually improve theelectrical connection by re-heating each lead for 4 to 5 seconds.
Similarly, check T1’s two windings (1-2 and 3-4) for
continuity. Then check T2's windings.

i

Toroidal inductor L1 (VFO) will not be installed until the
VFO is aligned in Alignment and Test Part I (page 36).

ELECRAFT33

On the top side of the RF board, locate the hole identified as(A) in Figure 6-9. (The label "S1" appears near the hole.)

(B)

(B)
(A)

i

When working with the side panels in the following steps,
place a soft cloth on your work surface to protect the paint. (Aclean anti-static mat will also suffice.)
Locate the two side panels and arrange them as shown in
Figure 6-10, with the inside surfaces facing up. The right side can be
identified by the presence of an extra hole as shown. The
illustration also shows where 2-D fasteners will be installed, as wellas the areas which were masked during painting.

J6
Left side, inside surface
2-D Fastener

Masked area
Right side, inside surface
Figure 6-9
Install a 7/16" (11 mm) hex male-female standoff on the topof the board at location (A) as shown. Use an internal-tooth lockwasher and 4-40 nut on the bottom. Do not over-tighten the
hardware; the standoff threads can be easily stripped.
Install 7/16" (11 mm) hex male-female standoffs at the two
locations identified as (B) in Figure 6-9, replacing the existing
3/16" pan-head screws. Do not use any lock washers.
Temporarily place the Filter board assembly on top of thethree standoffs just installed. If the standoffs are in the correct
positions, they will be visible through their holes in the Filter board.

Extra hole
Figure 6-10
Remove any masking tape from the panels using the same
technique described on page 23, taking care not to scratch the outersurfaces.

ELECRAFT

34

i

Flat-head screws are more easily damaged than panheads. Do not use excessive force when tightening them.
Attach two 2-D fasteners to each side panel at the locations
indicated in Figure 6-10. (Make sure that the holes are countersunk;
if not, you may be working with the wrong side of the panel.)Use one 3/16" (4.8 mm) flat-head screw to hold each 2-D fastenerto the side panel (Figure 6-11). The two unused holes on eachfastener must be offset away from the side panel as shown.

Attach the side panels to the RF board using two 3/16" (4.8mm) flat-head screws per side panel. The side panels are attachedusing the 2-D fasteners that are already in place on the RF board.
Figure 6-12 shows the approximate location of the two screws used
to secure the right side panel.

Holes offset
away frompanel

Figure 6-12
Figure 6-11

ELECRAFT

35

With the assembly upside-down or resting on one side, plug thefront panel assembly into the RF board (Figure 6-13). Connector J1
on the bottom of the front panel PC board mates with P1 on thebottom of the RF board (indicated by an arrow below).

i

The switches should now be accessible, and the headphonejack should be even with the front panel. Also, the LEDs above the
VFO knob should be visible. If any of these controls are notproperly situated, you may not have the Front Panel fully plugged
into the RF board.
Note: The coaxial jumper to be installed in the following steps isreferred to as W1 in the RF board parts list.
Cut a 2.6" (67 mm) length of RG-174 coax cable. Using a
sharp tool, remove about 3/8" (9 mm) of the coax jacket fromeach end. Be careful not to nick the braid.

Figure 6-14
Separate the braid (shield) from the center conductor at bothends (Figure 6-14). Clip off about half the strands of the braid close
to the jacket, then twist the remaining braid into a fine bundle.
Remove a small amount of insulation from the center
conductor. Use long-nose pliers to hold the center conductor while
stripping it, or you may pull it out of the coax jacket.
Figure 6-13

Secure the front panel to the side panels and RF board using two
flat-head and two pan-head 3/16" (4.8 mm) screws. Flat-headscrews are used on the top, and pan-head on the bottom. You may
need to adjust the 2-D fasteners slightly, then re-tighten all
hardware.

On the bottom of the RF board you'll find the component
outlines for two 2-pin connectors, J9 and J10. Install the coax cableon the bottom of the board between these two points. The center
conductor should be inserted into pin 1 of each connector (squarepad), and the braid into pin 2 (round pad). Do not solder yet.
Make sure that the coax braid is not touching any adjacentpads at either end, and that the coax is not covering the nearby
screw mounting hole. Solder the coax (on the bottom side of theboard). Trim the leads on the top side if there is excess lead length.

ELECRAFT

36

7. Alignment and Test, Part I
In this section you’ll become familiar with K1 operation, while
testing control circuits and aligning the VFO and receiver.

The Tap/Hold Rule
Each of the push-button switches on the front panel has twofunctions, one activated by a TAP (short press) and the otheractivated by a HOLD (long press, about 1/2 second). The upperlabel on each switch shows the TAP function (white lettering), andthe lower label shows the HOLD function (yellow lettering). To
highlight this in the text, we use two different typographical styles
to identify switches: T A P and H O L D .

Initial Testsi

If any test or alignment step fails, refer to the
Troubleshooting section (Appendix E).
To improve the visibility of the LCD during testing, you
should prop up the front edge with a non-conductive object (smallbox, book, etc.). Note: Do not attach the KTS1 tilt stand at thistime. With the bottom cover removed, it could cause a short.
Set AF GAIN fully counter-clockwise (minimum volume).
Make sure the K1 is turned OFF (power switch S1 out).
Plug your power supply or battery into J4 on the rear panel.

LED Testi

When you turn the K1 on the next step, watch for the
LED test. You should see the ATTN (yellow) LED turn on briefly,
followed by the RIT/XIT dual-color LED (green, then orange).
Turn on power to the K1. If you see or smell smoke, or acomponent feels hot to the touch, disconnect the powersource immediately. Locate the source of trouble before
proceeding.
If you did not see the LED test, refer to Troubleshooting.
LCD and Error Codes
You should now see E2 7 on the LCD. This is an error code
which occurs when the K1 self-test finds that the Filter board is notplugged in. (Error codes are listed and described in the
Troubleshooting tables.)i

If the LCD is blank, it may indicate that one or more
switches are closed. Check for shorts on all switch lines.
Tap any switch to clear the error code. You should then see
E4 2 , which indicates that the self-test found the VFO signal
missing. This is correct, since the VFO inductor, RF-L1, has not yet
been installed. (When the VFO is functioning normally, you'll see
the operating frequency displayed.)

ELECRAFT

37

Sidetone Generator and Audio Amplifier

Keyer

Plug in a pair of stereo headphones, and rotate the AF GAIN
control clockwise to about 9 or 10 o’clock.

Note: If you don’t have a keyer paddle, you can still test the DOT
and DASH lines by using test clips to touch them to ground.

Tap M E N U . The first menu entry will be displayed: O UT(transmit power output). Tap W P M + to select the next menu
entry, S T L (sidetone volume). (Lower-case "t" is used.)

Plug a keyer paddle into the key jack (J3). The plug must be
stereo (2 circuit). A stereo plug is supplied with the kit.

The Sidetone can be activated by editing the S T L menu
parameter. Hold E D I T to show the parameter and turn on thesidetone. You can then use W P M + and W P M - to vary the sidetone
level, from 0 -3 1 . Select a comfortable level, then tap M E N U toturn off the sidetone and return to the S T L display.
Note: S T L is used to set the sidetone volume level in relation tonormal received audio. However, the AF GAIN control sets theoverall headphone or speaker volume.

Tap M E N U and locate the I NP menu entry (CW input device
selection). Hold E D I T to see the parameter, which defaults to Hn d(hand key or external keyer). Use W P M + and W P M - to select either
P Dn or P Dr (paddle normal, or paddle reverse). Then tap M E N U
twice to return to the VFO display.
Select the keyer speed using W P M + and W P M - . If you tap
these switches quickly, the speed will jump 2 WPM at a time.
While listening with headphones, test the keyer paddle toverify that both dot and dash are working.

Select the sidetone pitch menu entry (STP) using by tapping
W P M + . Hold E D I T to turn on the sidetone and edit the pitch

parameter. The pitch can be varied from 4 0 0 to 8 0 0 Hz using
W P M + and W P M - . Select the desired pitch, then tap M E N U to end
parameter edit and return to S T P .
Tap M E N U again to return to the normal display (in this caseE4 2 because of the missing VFO signal).
Voltmeter
On power-up, the LCD shows the operating frequency, with
100-Hz resolution. Holding D I S P L A Y once selects S-meter mode.
Holding D I S P L A Y again selects voltmeter mode. You should see
BA T flash briefly on the LCD, then your approximate power
supply or battery voltage, which will continue to flash slowly.
Return to the operating frequency display by holding
D I S P L A Y again. You should see E4 2 , as explained previously.

If you use a dual-lever keyer paddle, you may wish to use themenu’s I A B entry to select iambic mode A or B (page 55).
Relays (Filter Board and Attenuator)
Turn off the K1.
Plug in the Filter board assembly. The connectors on the Filter
board must be fully inserted into J6, 7 and 8 on the RF board.
Turn the K1 on. The LCD should show E4 2 . You may also
hear one or more relays switching.
Tap B A N D twice (quickly) to change to the next band. Tap
B A N D two or more times quickly to return to 7 . 0 MHz.
Test the attenuator relay and the yellow LED by holding
A T T N . Hold A T T N again to turn the attenuator off.

ELECRAFT

38

VFO Alignment

VFO Range Test

Turn the K1 off and disconnect the power supply.
Two different capacitors are supplied for setting theapproximate VFO range: C2 (68 pF disc) and C2A (120 pF
polystyrene). 68 pF provides a range of about 80 kHz; 120-pF
provides a range of about 150 kHz. Other values can also be used(builder-supplied).
Based on your VFO range selection (page 12), install theappropriate capacitor at C2. Save the other for possible future use.
If you use the 68-pF disc cap, pre-form the leads to match the padspacing for C2.
Wind L1 on a T50-6 toroid core (yellow, 1/2" [12 mm]diameter). Use 24 inches (61 cm) of red enamel wire. Wind 33
turns on L1, leaving the two leads about 1/2" (12 mm) long.
Adjust the turns of L1 so that they are fairly evenly spaced
and occupy about 90% of the core.
Strip and tin the leads of L1 to within 1/8" (3 mm) of thecore. (Review toroid lead preparation instructions, page 14.)
Secure L1 loosely to the PC board as indicated by its
component outline, near J6. As shown in Figure 7-1, use two nylon
washers, a 1/2" (12 mm) nylon screw, and nylon 4-40 nut.

Tap M E N U and locate C A L . To enable the operating
frequency calibration display (O P F), hold E D I T . The 100-Hz digit
should be flashing. (If you see E4 2 , the VFO is not functioning.)
To see the VFO frequency, you’ll use CAL’s other display
mode, O S C . To select this, hold D I S P L A Y . You’ll see O S C ,followed by the VFO frequency in MHz (1 digit), then kHz (3digits). For example, 3.012 MHz would be shown as 3 , then 0 1 2 .
Make sure that the VFO frequency goes up as the VFO knob isrotated counter-clockwise. If not, see Troubleshooting.
Rotate the VFO knob fully clockwise until it stops, then notethe frequency: __________ kHz. Rotate it counter-clockwise until
it stops and note the frequency: __________ kHz. Subtract the
low reading from the high reading to obtain the VFO range:_________ (about 80 or 150 kHz, depending on the value of C2).
VFO Range Adjustment
Make sure the VFO knob is rotated fully counter-clockwise.
If the frequency shown is now higher than 3.100 MHz,squeeze the turns of L1 (bunch them more closely together) tolower the frequency. You can squeeze the turns by hand, or use thetuning tool. Watch the frequency display as you adjust the turns.
If the frequency shown is lower than 3.090 MHz, spreadthe turns of L1 out. This raises the VFO frequency. If the frequency
cannot be raised to at least 3.090 by spreading the turns out, you
may need to remove one turn from L1 (the non-grounded end).

Figure 7-1
Insert L1’s leads into their pads and solder.
Connect the power supply and turn the K1 on.

Note: The final VFO frequency should be between 3.090 MHz and3.100 MHz to make sure that the low end of each band is covered.
Once the turns on L1 have been correctly adjusted, tighten thenylon screw so that the L1’s turns are held firmly in place. (Thismay shift the indicated frequency slightly.)

ELECRAFT

39

Band Assignments

Receiver Alignment

To see the correct display when you tap B A N D , you’ll need to
specify which bands are covered by your Filter board.

This section applies only to the two-band Filter board.
If you have a four-band Filter board installed, refer to the
KFL1-4 manual, page 17.

If you re still in the C A L menu entry, tap M E N U to exit.
Locate the B1 menu entry (note that the "b " actually appears
in lower-case). If B2 , B3 , or B4 is shown, tap B A N D to change it
to B1 .
To check the present assignment for band 1, the lowestfrequency band, hold E D I T . The default is 7 . 0 MHz. Use W P M + or
W P M - to specify band 1.

i

On 30 meters, you have a choice of two band edges (1 0 . 0
or 1 0 . 1 ), depending on your VFO range selection (from page 12).
The appropriate band edge is set by holding D I S P L A Y .
Tap M E N U to return to the B1 display, then tap B A N D toswitch to B2 . Hold E D I T again to show the band 2 assignment.
Use W P M + and W P M - to specify band 2. If band 2 is 30
meters, select the band edge using D I S P L A Y .
In the same manner, specify band 3 and band 4, if applicable(four-band module only; see KFL1-4 manual, page 16).
Tap M E N U twice to exit the menu.
To re-check the band assignments, tap B A N D . The current
band will be displayed (in MHz), followed by a 3-digit display (1kHz resolution), followed by the normal frequency display (to 100
Hz). For example, if the band is 40 meters and the VFO is set to7025.3 kHz, tapping B A N D will show 7 , then 0 2 5 , and finally
2 5 . 3 . Tapping B A N D twice (quickly) switches to the other band.

Set the BFO trimmer, C20, so that its adjustment slot isparallel to the nearby crystal. (C20 is located near the front edge of
the RF board.) The final setting of C20 will be determined later.
If the present band is not band 1 (the lower frequency band),tap B A N D twice quickly to select it.
Make sure that the attenuator (yellow LED) is off.
Plug in a pair of headphones or an external speaker, and adjust
the AF GAIN control until you hear some background noise. If you
do not hear any background noise, refer to Troubleshooting.
Set the VFO to about the mid-point of the present band (7.050
MHz on 40 meters, 10.125 MHz on 30 meters, etc.). Tap B A N D if
necessary to verify that you’re in the right 100-kHz band segment.
Connect an appropriate antenna for band 1. At minimum,
connect approximately 20-30 feet (6 to 9 meters) of any type ofwire to the center conductor of J5. In general, the longer and higher
the antenna, the more signal strength that will be available during
receiver alignment.

i

Receiver alignment will be easiest if you use a ham-band
transmitter or signal generator to create a very strong signal thatcan be located with the K1. If you use a transmitter, be sure toconnect it to a dummy load and operate it at low power.

ELECRAFT

40

Band-Pass Filter Alignment
On the Filter board, there are premix filters and RF filters for eachband, as shown in Figure 7-2. Each filter has two slug-tuned
inductors. These filters will be peaked in the following steps.

PremixWhile listening to noise or a weak signal, peak the band-2
Premix inductors, L3 and L4.
Peak the two band-2 RF inductors, L7 and L8.
Re-peak L3 and L4, then L7 and L8, until no further
improvement is noted.

RFBand 1
Band 2

Figure 7-2
Locate the plastic tuning tool. The smaller end of the tool will
be used to adjust the slug-tuned inductors.
While listening to atmospheric noise or a CW signal, peak thetwo band-1 Premix inductors, L1 and L2. Do not continue to turnthe slug if it has bottomed-out. Stop when you feel resistance. If
you cannot find a peak for L1 and L2, set them to about the midpoint of their range for now and go on to the next step.

Coarse BFO Alignment
The K1 three crystal filter bandwidths are selected by holding
the X F I L switch. Hold X F I L until you see FL 3 on the LCD.
Note: FL1, 2, and 3 are pre-set to bandwidths of about 800, 400,
and 250 Hz. They can be set up differently using FL x (page 53).
Tune in a moderately-strong signal. Adjust the VFO slowly tofind the pitch where the signal is strongest. At this point, the signal
will be centered in the crystal filter.
Locate the BFO trimmer, C20, near the front edge of the RF
board. Adjust C20 for approximately the desired signal pitch.
Fine BFO Alignment Using the Sidetone Pitch
Select your desired sidetone pitch using the S T P menu entry.
(Many CW operators use 500-600 Hz or lower.) Exit the menu.

Peak the two band-1 RF inductors, L5 and L6. If no signals areheard while peaking either L1/L2 or L5/L6, use a transmitter togenerate a stronger signal, or scramble the settings and try again.

Tune in a strong signal, adjusting the VFO slowly until thesignal strength is centered in the filter, as you did above.

Re-peak L1 and L2, then L5 and L6, until no further
improvement is noted. Once all four inductors have been peaked,
received signals and noise should be quite strong.

Turn on the sidetone again using the S T P menu entry.

Tap B A N D twice (quickly) to select band 2.
Switch to an appropriate antenna for this band, if available,
and set the VFO for the mid-point of the band.

Adjust C20 so that the pitch of the received signal matches
your sidetone pitch. This is best done with both the received signal
and sidetone at about the same amplitude. The received signal willseem to "disappear under" or "merge with" the sidetone when thepitch is closely matched.
Tap M E N U twice to return to normal operation.

ELECRAFT
Operating Frequency Calibration
The operating frequency display may be off by up to 10 kHz until
calibrated, due mostly to variations in the crystals on the Filter
board. Accuracy of +/- 100 Hz can be obtained.
Note: The approximate lower band edges in MHz are as follows:
3.50, 7.00, 10.00 or 10.10 (selected earlier), 14.00, 18.05, 21.00.
Select the lower-frequency band using B A N D . Also select thenarrowest filter (FL 3 ) by holding X F I L .
Tune in a signal at a known frequency, centering the signal in
the crystal filter passband. Use a signal from a known-accurate
signal generator, or check the signal’s frequency using a second
receiver.

41
AGC (Automatic Gain Control) and S-Meter Test
Turn the K1 on and connect an antenna or signal generator.
S-meter display mode provides a bar graph to indicate
approximate received signal strength. To select this mode, holdD I S P L A Y . You should see a brief bar-graph test pattern, then thedisplay may go blank or show one or more bars.
Tune in a strong signal. (Anytime you are actually moving theVFO, the S-meter bargraph will be replaced with the frequency
display.) Once the signal is tune in, the AGC should be activated, as
indicated by an increase S-meter reading.2 The S-meter zero point
and scale can be adjusted (page 53). AGC can also be turned off ifnecessary (page 57).

To access the operating frequency calibration display, locate
C A L in the menu, then hold E D I T . You’ll see O P F briefly, thenthe operating frequency will be shown, with the 100-Hz digit
flashing. (If you see E4 2 , the VFO is not functioning.)

Note: Since the K1 uses audio-derived AGC, the initial code
element from a very strong station may be heard at louder volume.
This is due to the time it takes for the AGC detector capacitor to
charge up. If this is objectionable, the attenuator can be used.
Turning on the attenuator adds one bar to the S-meter reading toroughly compensate for the loss in signal strength.

Tap W P M + or W P M - until the displayed frequency matches
the frequency of the known signal. In the case of the internallygenerated signal, tap W P M + or W P M - until the display reads 9 9 . 7 .

Receive Current Drain Test (Optional)

Tap M E N U twice to return to the normal display.

Typical current drain for the K1 in receive mode is approximately
55 mA (with all LEDs off). If the current drain is significantly
lower or higher than this, it could indicate a problem.

Tap B A N D twice quickly to switch to band 2.
Repeat the calibration procedure on this band. If you have a 4band Filter board installed, repeat the procedure for bands 3 and 4.

i

You can calibrate the dial on transmit rather than receive if
desired, after completing Alignment and Test, Part II. In this case
you ll need either a frequency counter or a calibrated ham-bandreceiver to verify the actual transmit frequency. You ll then use theC A L menu entry, as described above, to check and adjust theoperating frequency after each transmission.

To check the current drain, set your DMM for DC milliamps andtemporarily insert the DMM in series between the K1 and thepower supply. Turn the K1 on and note the current: _____ mA.
This completes receiver alignment.

2

Each bar corresponds to roughly two S-units, so that 4 or 5 bars indicates
about an "S-9" signal.

ELECRAFT

42

8. RF Board, Part II
In this section you’ll install the transmitter components.
Turn off the K1 and disconnect the power supply.
Unplug the Filter board and set it aside.

i

If you have difficulty installing components in theremaining assembly steps, unplug the Front Panel assembly andremove the side panels.
Install the following capacitors, starting with C3, which is in
the back-left corner of the RF board.
__ C3, 10 (10)⇒__ C15, .001 (102)__ C14, .001 (102)__ C76, .01 (103)__ C44, .01 (103)__ C55, 0.1 (104)__ C62, 330 (331) ⇒__ C58, .01 (103)__ C16, .001 (102)__ C57, .047 (473)__ C46, 0.1 (104)__ C52, 0.1 (104)__ C56, .047 (473)__ C51, .001 (102)__ C60, .01 (103)__ C47, .01 (103)__ C50, .047 (473)__ C43, .01 (103)Install the following 5% resistors, starting with R35 on the left
side of the board near J6.
__ R35, 120 (BRN-RED-BRN)⇒ __ R10, 470 (YEL-VIO-BRN)__ R11, 82 (GRAY-RED-BLK)__ R22, 33 (ORG-ORG-BLK)__ R12, 820 (GRAY-RED-BRN)__ R24, 2.7 k (RED-VIO-RED)__ R38, 270 (RED-VIO-BRN)__ R28, 820 (GRAY-RED-BRN)__ R29, 270 (RED-VIO-BRN)__ R30, 3.3 Ω (ORG-ORG-GOLD)__ R33, 470 (YEL-VIO-BRN)__ R25, 100 k (BRN-BLK-YEL)__ R31, 33 (ORG-ORG-BLK)__ R32, 33 (ORG-ORG-BLK)

On the bottom of the board near the antenna jack, install a
1.50 k, 1% resistor at R36 (BRN-GRN-BLK-BRN), and a 226-ohm,
1% resistor at R37 (RED-RED-BLU-BLK).

i

Be sure to check the orientation of the banded end of each
diode in the following steps.
Install the 36-volt zener diode, D19 (type 1N4753), which has
a large glass or silver-colored body. D19 is on the right side of theboard, between transformers T3 and T4 (not yet installed).
The remaining diodes to be installed are all type 1N4007. D18
is on the left side of the board, near J6.
__ D18__ D14__ D13__ D9

Install a 100-µH RF choke (BRN-BLK-BRN) at RFC3 (locatednear S1).
Install 22-µH RF chokes (RED-RED-BLK) at RFC2 and RFC5.
Refer to Figure 5-4 (page 19) when installing these transistors.
__ Q5, J309 (near J6)__ Q14, 2N4124 (back-left corner)

Install C1 (150 pF, “151”) on the bottom of the board. Before
soldering, fold C1 down towards the pads of R31 and R32 (but makesure it isn’t touching these pads). C1’s overall height should be no
more than 0.15” (4 mm) above the bottom of the board.

ELECRAFT

43

i

TO-220 package transistors Q6 and Q7 look identical, but are
different types. Locate the 2SC1969 (labeled "C1969"), Q7, and set it
aside. The remaining transistor, Q6, will be either a 2SC2166 (C2166)
or a 2SC5739 (C5739). This transistor will be installed first.
Attach a self-adhesive thermal pad to the PC board on top of thecomponent outline for Q6. The hole in the thermal pad must be aligned
precisely with Q6's mounting hole on the board.

Identify the hole in the right side panel where the thermal
insulator will be placed (Figure 8-2). If the edge of the hole is notcompletely smooth, use a large drill bit to de-burr the hole by hand.
Follow with a small amount of light sanding of the indicated area.
Attach a self-adhesive thermal pad to the side panel at thelocation shown in Figure 8-2. The hole in the thermal pad must bealigned precisely with the hole in the panel. The pad must be straight,
not tilted or skewed in either direction.

Prepare the leads of Q6 as shown below, bending themdownwards to match their pads. To avoid stressing the leads, usesmooth bends, rolling them over a small screwdriver blade or forming
them using long-nose pliers.

Use smoothbend, not 90°

Thermal insulator

Figure 8-2

Figure 8-1

Attach Q7 to the right side panel using the hardware shown in
Figure 8-3: a 5/16" (8 mm) x 4-40 flat-head screw, shoulder washer(black plastic), #4 internal-tooth lock washer, and 4-40 nut. The smalldiameter part of the shoulder washer must be inserted into the holein Q7's tab. Do not over-tighten the hardware.

Secure Q6 to the board using a 4-40 x 3/8" (9.5 mm) pan-headscrew (shiny finish, not black), #4 internal-tooth lock washer, and 4-40
nut. The screw should be inserted from the bottom side (Figure 8-1).
Verify the part number on Q6 (2SC2166, C2166 or 2SC2166,
C2166), then solder. Trim the pins on the bottom.
Remove the right side panel if it is still attached.
Figure 8-3

ELECRAFT

44

Bend the center lead of Q7 slightly away from the side panel,
forming it as shown in Figure 8-3.
Hold the right side panel up to the right edge of the RF board.
Insert Q7's leads into their pads while guiding the panel into
position. Secure the right side panel to the RF board using two
3/16" (4.8 mm) flat-head screws.

T3 is wound on an FT37-43 core (dark gray), the smaller of
the two cores remaining. Start with the 1-2 winding, which uses 12
turns of red enamel wire (9", 22 cm). See Figure 8-4.
3, GRN
1, RED

Solder and trim the leads of Q7 on the bottom of the board.
Using an ohmmeter on a low resistance scale, check for ashort from Q7's tab to ground. (The tab is connected to thecollector lead.) The metal hardware used to hold Q7 to the sidepanel may show low resistance to ground, but the tab should befloating (> 1 k).
Install 8-pin ICs U8 (SA602 or SA612AN) and U9 (LT1252).
Orient the ICs as indicated by their component outlines.

i

Toroidal transformers T3 and T4 must be wound exactly as
described in the following steps. Recall that transformer windings
are identified by numbered pairs of leads, which correspond to thenumbered PC board pads.

2, RED
4, GRN

Figure 8-4

T3's 3–4 winding uses 4 turns of green enamel wire (6", 16cm). The turns of the 3-4 winding must be tightly interlaced withthe 1-2 winding as shown in Figure 8-4.
Strip and tin T3’s leads.
Install T3 flat against the PC board, to the right of Q6. Pull
the leads taut on the bottom side before soldering.

ELECRAFT

45

i

T4 uses a bi-filar winding, which means that two wires arewound on the core together. The wires for the two windings will be
twisted together (see Figure 8-5).

If you plan to operate the K1 on 80 meters, and your K1 RF
board is revision D or earlier, you may need to make a minor
modification to the PC board. Please refer to the errata sheet included
with the K1B80 (80-m Band Kit).

Uninstalled Components

1
(RED)

2
(GRN )

3(RED)

4(GRN )

Figure 8-5
Cut two 8" (20 cm) lengths of enamel wire, one red and one
green. Twist the wires together over their entire length. The wires
should cross over each other approximately every 1/2" (1 cm).
Wind the twisted wires onto the 1/2" (12.7 mm) dia. ferrite core
(FT50-43, dark gray), using 5 turns and covering about 85% of thecore. Figure 8-5 shows how the winding should look.
Separate T4’s leads as shown in Figure 8-5. Strip and tin theleads. Be careful not to let the red and green wires short together.
Install T4 flat against the PC board as indicated by its outline.
Using your DMM on a low resistance scale, measure continuity
between the #1 and #2 pads of T3. If you get a reading over 5 ohms,
re-strip the affected lead(s). Similarly, check the 3-4 winding of T3.
Then check T4's 1-3 and 2-4 windings.

Make sure that all component locations on the RF board havebeen filled, except for two: J1, which is supplied with the noiseblanker option kit (KNB1), and C78, which may be supplied with the
80-m band kit for the 2-band Filter board. If you have the 80 meterboard, install C78 at this time on the bottom of the board near the PA
and 12V labels with the (+) lead oriented as shown on t he outline.
Fold C78 down flat against the board before soldering.

Visual Inspection
Examine the bottom (solder side) of the RF board carefully for
unsoldered pins, solder bridges, or cold solder joints.

Resistance Checks
For the following measurements, connect the (-) lead of yourDMM to a ground jumper. When making measurements at J7 and J8,
use a component lead or hookup wire as a probe tip.
Test Points (+)
J7 pin 1J7 pin 4J7 pin 5J7 pin 6J7 pin 8J8 pin 1
J8 pin 5J8 pin 7
U4 pin 7
U8 pin 8
U9 pin 7D9 cathode (banded end)
D9 anode

Resistance
2.4-3.0 k>1k> 100 k5-7k
1.5-2.0 k> 100 k90-110 k
1.6-1.9 k>1k> 100 ohms
>1k
1.5-2.0 k> 100 ohms

ELECRAFT

46

9. Alignment and Test, Part II
In this section you’ll align and test the transmitter stages.
Turn off the K1. Plug in the Filter board.
Attach the side panels, then plug in the Front Panel assembly.
Connect an antenna that is adequate for receiver testing.
Plug in a pair of stereo headphones or a speaker at J2.

Make sure the Filter board is not installed.
Place the power switch, S1, in the OFF position (out).
Connect a 12 to 14-V, 1-amp power supply (or battery) to J4.
Turn on the K1. You should see E2 7 on the LCD due to themissing Filter board. Tap any switch to clear the message.
Place the transmitter in TUNE mode (key-down), by holding
the W P M + and W P M - switches simultaneously. The display should
show 0 . 1 watts, even though actual power output is zero.
Make the following transmit-mode DC voltage measurements.
Connect the (-) lead of the DMM to a ground jumper. Note: Thebanded end of diodes is the cathode.
Test Point
J7 pin 1J7 pin 4J7 pin 6J7 pin 8U8 pin 1
U8 pin 8
U9 pin 3
U9 pin 6
U9 pin 7

DC Voltage
5.1-6.7
5.9-6.1< 0.2
3.8-4.1
1.3-1.5
5.1-5.5
6.0-7.0
6.0-7.0
12-14

Test Point
D9 anodeD9 cathodeD10 anodeD10 cathodeD11 anode
D11 cathodeD13 anodeD13 cathodeDC Voltage
4.3-4.6
3.8-4.1< 0.2
3.8-4.1< 0.2
4.0-4.6
0.6-0.7< 0.2

Turn on the K1 and test receive performance. If receiver gain
seems to be too low, you may have an assembly error in thetransmit stages or T-R switch. Remove the Filter board and recheck the orientation of all diodes, transistors, and ICs. Also look
for shorts on both the top and bottom of the board in thetransmitter area. (Also see Troubleshooting.)
Switch to the voltmeter display to make sure that the battery
or power supply voltage is not being pulled down when the K1 isturned on. (Hold D I S P L A Y once to select S-meter mode, and asecond time to select voltmeter mode.)
Preparation for Transmit Alignment
Turn the K1 off. Secure the Filter board to its three standoffs
using 3/16" (4.8 mm) pan-head screws and #4 split lock washers.
Connect a 50-ohm dummy load at the antenna jack. The
dummy load should be rated at 5 watts or higher.
Connect a key or keyer paddle.
Turn the K1 on.
Tap M E N U and locate the O UT entry (power output level).
Hold E D I T , then use W P M + and W P M - to set power to 2 . 0 watts.

ELECRAFT
Band 1 Alignment

47
Band 2 Alignment

If a 4-band Filter board is in use, refer to the KFL1-4 manual, page 19.

Switch to band 2, and set the VFO to about mid-band.

All filters are shared between receiver and transmitter, so transmit
alignment should already be close. However, it's important to repeak the filters on transmit. An analog wattmeter, ham-bandreceiver, or the K1’s built-in digital wattmeter can be used.

Put the K1 into TUNE mode and adjust L3, L4, L7, and L8
for maximum output (refer to Figure 7-2 if necessary).

Switch to lower-frequency band using B A N D . Set the VFO toapproximately the middle of the desired band.

5-watt Test

Refer Figure 7-2 to identify the band 1 inductors.

iVerify that the K1 is transmitting at the intended frequency.

Set power output to 5 . 0 watts using the O UT menu entry.
Enter TUNE mode briefly. The wattmeter should display
approximately 5 watts. Test 5-watt output on both bands.

The K1 can be placed in TUNE mode by holding theW P M + and W P M - switches together. During TUNE, the power inwatts will be shown on the LCD (e.g., P 2 . 0 ). Hitting the key orpressing any switch except W P M + and W P M - will cancel TUNE.
Put the K1 into TUNE mode. Using the alignment tool, adjust
L1, L2, L5 and L6 for maximum output. If the output jumps up to
well above 2 watts, exit TUNE mode, then re-enter it again.3
If necessary, repeat the adjustment of the filters two or threetimes to be sure that you have the inductors peaked correctly. If
output is < 2 w or is not stable, see Troubleshooting.
If possible, verify that the K1 is transmitting on the correct
frequency using an external ham-band receiver. Connect a shortlength of wire to the receiver's antenna jack. (Do not connect theK1 directly to the receiver.) Key the K1 and locate the signal.
To make sure that the filters are peaked at the correct
frequency, vary each inductor a small amount while observing thereceiver's S-meter.

Transmit Offset Adjustment
Locate the offset test switch (S2) on the bottom of the RF
board. Place it in the TEST position. You should hear a tone in theheadphones; its pitch is equal to the transmit offset. If you don’t
hear a tone, try rotating C13 (back left corner, near the key jack).
Using the menu, locate S T P (sidetone pitch), and go into edit
mode to turn on the sidetone. You should now hear two tones: thesidetone and the transmit offset tone. If the sidetone is very weakor very strong compared to the transmit offset tone, use the S T L
menu entry to adjust the sidetone volume. Note: The receiver ismuted in S T L edit mode, so you'll have to return to S T P after
making any change to the sidetone setting.
Adjust C13 so that the transmit offset pitch is as close as
possible to your selected sidetone pitch. The two will seem to"merge" when the pitches are matched.
Exit the menu, and set S2 back to the OPER position.
If necessary, use the C A L menu entry to calibrate theoperating frequency on transmit (see page 41).

3

The transmitter's ALC (automatic level control) attempts to set the power
you specify. ALC is activated for 1-2 seconds when you enter TUNE mode.
After that, it is "open-loop," allowing you to adjust the filters. If the power
jumps, re-starting TUNE mode will activate the ALC again, reducing thedrive back down to the level needed to stay at about 2 watts.

This completes transmitter alignment.

ELECRAFT

48

1. Final Assembly
Remove any masking tape from the top and bottom covers. Use
the technique described on page 23.
Remove and save the hardware supplied with the antenna and key
jacks.
The components on the bottom of the board must have an overall
height of no more than about 0.2” (5 mm) above the PC board. Fold
down or re-solder components if necessary.
Install the bottom cover by sliding it over the rear-panel controls.
Secure it to the rest of the assembly using six 3/16" (4.8 mm) pan-headscrews.
Install the hardware supplied with the antenna and key jacks. Be
careful not to strip the plastic threads on the antenna jack.

Figure 10-1

Set the top cover upside-down in front of you, with the back edge
facing away. Place the speaker over its holes, with the lugs to the left.
(Figure 10-1) .
Trim the speaker grille cloth so it is the same size as the speakerframe and then trim the corners so it fits between the fiber washers.
Keep the grille cloth in place as you secure the speaker to the top
cover using four 5/16" (8 mm) flat-head screws, #4 fiber washers(black), #4 metal flat washers, #4 internal-tooth lock washers, and 440 nuts (Figure 10-2). The fiber washers go between the speaker andthe top cover. Do not over-tighten the nuts, as this can flex the
speaker frame, causing damage to the speaker and/or distorted
audio.

lockwasher

metal flat washer

fiber washer
Figure 10-2

ELECRAFT

49

Cut a 5" (13 cm) length of two-conductor speaker cable.
Remove 1/4" (6 mm) of insulation from the wires at both ends.
Solder crimp pins to the two wires at one end (Figure 10-3).

Copper wirePin 1 side

Plug the internal speaker cable into P2 on the RF board. The
connector is keyed and can only be plugged in one way.

i

When you install the top cover in the next step,route the speaker cable along the right side of the cabinet,away from the pins of the microcontroller (front panel, U1).
The speaker wire could pick up signals from the microcontroller,causing receiver interference.
Place the top cover onto the chassis. Secure the top coverusing two pan-head and two flat-head 3/16 (4.8 mm) screws.

Crimp pin

Housing

Figure 10-3

Four self-adhesive feet are supplied for the bottom cover.
Install one at each corner, approximately 1/4" (6 mm) from edges.
Attach the self-adhesive serial number label to the rear panelof the bottom cover in the space provided.
Write the serial number on the inside cover of your manual.

i

When you insert the crimp pins into the housing in thenext step, they should snap into place. Each pin has a small tab on
the back that latches into a hole in the housing when inserted.
Insert the copper wire into the pin 1 position of a two-pin
housing as shown. Insert the other wire into the pin 2 position.
Connect the other end of this cable to the speaker terminals.
The copper wire should be connected to the lug marked (+) on the
speaker. Solder both wires.
If there are any missing chassis screws in the bottom cover,side panels, or front panel, install them now.

If you have the KTS1 wide-range tilt-stand, you should
configure it for desk-top use (using the short arms) and attach it to
the K1 at this time. Refer to the KTS1 instructions.
This completes assembly of your K1 Transceiver. You should have anumber of washers, screws, and other hardware left over. These
items have been provided as spares. Please read the Operation
section, which follows, and try each of the K1's features. If you're
new to QRP, be sure to read the QRP Operating Tips (page 56).

i

If you have purchased K1 internal options, we recommendthat you do not install them until becoming familiar with basic K1
operation. Once you're ready to build option kits, the suggested
order of assembly is: KFL1-2 or KFL1-4, KAT1, KNB1, KBT1.
(All K1 options are described on page 57.)

ELECRAFT

50

11. Operation
This section explains how to set up and operate the K1. We suggest
you read the first few pages as an overview, then follow thetutorial, which starts on page 54 (Basic K1 Operation). There's alsoa Quick Reference, Appendix G, which shows the locations offront-panel controls and describes each of the menu entries.

Connections
Power Supply
You can use any 9-15 V DC power supply; current drain is about
0.5-1A on transmit. A mating DC power connector is provided
with the kit. Use an in-line 2A fuse when operating from abattery or power supply that does not include its own fuse.
Low Battery warnings: If your battery (or power supply) voltage
drops below about 9 V, you’ll see a brief BA T L O message flashedon the LCD once every 5 minutes (approx.). This voltage level waschosen to be compatible with an 8-cell NiMH or NiCd battery back.
Other battery types may have a different end-of-life
voltage; check the voltage using BAT display mode often.
12-V gel-cell batteries must be recharged at 10.5-11.0 V.

Headphones or External Speaker
The front-panel headphone jack can accommodate either
headphones or an external speaker, with an impedance of 8 ohms
or higher. A stereo plug or mono/stereo adapter is required,
unless you modify the RF board (see 2nd step on page 31).

Keying Device
Any type of hand key, bug, or external keyer can be plugged into
the KEY jack, or you can connect a paddle and use the K1's built-in
memory keyer. In all cases, you must use a stereo plug with the
keying device (a suitable plug is provided with the kit). It is also
possible to connect both a keyer paddle and another keying device
at the same time; see Keying Device Selection (page 55).

Antenna
Any well-matched, unbalanced (usually coax-fed) antenna can beused with the K1. With non-resonant antennas or balanced
feedlines a suitable balun and/or antenna tuner will be required. If
you have the KAT1 automatic antenna tuner option installed, you
can connect a wide range of random length or non-resonant
antennas directly to the K1 and use them on one or more bands.
Power setting accuracy with internal RF detector: Powerreadings using the K1's built-in RF detector (D15) are only accurate
when the SWR is low. If you use a poorly-matched load, you should
check your power output with an external wattmeter. In some casesa high-SWR load can result in excessive current drain.
Power setting accuracy with KAT1: If you have the KAT1
installed, power output display will be much more accurate under all
SWR conditions, since the tuner provides its own calibrated SWR
bridge/wattmeter.

ELECRAFT

51

Controls and Display

Switch Functions

LCD

T A P a switch to access its upper function; H O L D a switch for 1/2
second to access its lower function. All functions are listed below.

The 3-digit LCD (liquid crystal display) shows the operating
frequency or relative signal strength (S-meter) on receive, power
output on transmit, menu parameters, and status information.
Decimal Point: The decimal point is flashed when RIT or XIT isenabled. This acts as a reminder that RIT or XIT is on.

The "1" and "2" labels near W P M + and W P M - correspond to CW
message buffers 1 and 2 (see M S G and R E C , below). The "T" labelnear these switches is a reminder that TUNE mode is activated byholding both W P M + and W P M - simultaneously (see page 54).
T A P and H O L D Switch Functions

Error Messages: If a problem is detected on power-up or during
normal operation, the display may show E4 2 or a similar message.
If this happens, see Troubleshooting.

B AND
DI S P LAY

show present band/freq.; tap twice to change bands
select display mode (normal, S-meter, or battery)LEDs

M E NUE DI T

enter the menu (see Menu)
edit current menu parameterRIT
X I T [ P Fn]

turn RIT on or off
turn XIT on or off, or select P Fn (see Menu)

Note: The LEDs can be disabled using the L ED menu entry. Thiscan save up to about 20 mA of receive-mode current drain.

W P M+X FI L

increment keyer speed or menu parameterselect next crystal filter (FL1-3)

VFO

W P MATTN

decrement keyer speed or menu parameter
attenuator on/off

The VFO covers about 80 or 150 kHz of each CW band, as selectedduring assembly. The approximate lower band edges in MHz are:3.50, 7.00, 10.00 or 10.10, 14.00, 18.05, and 21.00.

M SG
RE C

play CW message 1 or 2 (to repeat, hold 1 or 2 )record CW message 1 or 2 (M S G cancels record)

Potentiometers

Fast-Tap

AF GAIN: Sets the receive audio output level. It also affects thesidetone volume, in conjunction with the STL menu entry. Note:
The gain setting for headphones will be lower than for the speaker.

If you tap W P M + or W P M - two or more times quickly, the keyer
speed will change by two WPM at a time. In the O UT menu entry,
fast-tapping will change the power in 0.5-watt steps.

RIT/XIT (dual-color): RIT (green) or XIT (orange)
ATTN:
Attenuator (yellow)

OFFSET: Adjusts the offset when R I T or X I T is turned on. The
range is about +/- 3 kHz. (The range is set by RF-C7.)

ELECRAFT

52

Using the Menu
To access the menu, tap M E N U . Scroll menu entries by tapping W P M + / W P M - .
Hold E D I T to display a menu entry's parameter, which can then be changed by tapping W P M + / W P M - . Tap M E N U to return to scrolling.
Another tap of M E N U will return you to normal operation. If a parameter appears as "- - ", the associated option is not installed.
Edit Shortcut: If the menu entry you want is the last one you accessed, you can jump directly into edit mode by holding E D I T . After editing,exit by holding E D I T once more. Note: The AGC and NB parameters are not saved. On power-up, AGC is ON, and NB is OFF.
All menu entries are listed below. They are arranged so that the ones used most often are at the beginning and end of the list, allowing you to
get to them quickly by scrolling forwards or backwards. The FL x , Bx , C A L , and S I G entries are described under Calibration Functions.
O UTpower output level: 0 . 1 -7 . 0 watts(hold D I S P L A Y to select P = 0 , for keyer/msg test)

L ED

RIT/XIT/ATTN LEDs O N or O FF
(hold D I S P L A Y to turn switch audio tones on/off4 )ST L

sidetone level (volume): 0 -3 1

FL x

ST P

sidetone pitch: 4 0 0 to 8 0 0 Hz in 10 Hz steps(can also be used to SPOT, since RX is not muted)

crystal filter bandwidth, 2 0 0 -8 5 0 Hz
(hold X F I L to select FL 1 / 2 / 3 , thentap W P M + / W P M - to set bandwidth)

T-R

transmit-receive (QSK) delay: 0 to 9 0 0 ms
(50 ms recommended for casual operation)

Bxband assignments, in MHz (1 . 8 to 2 8 . 0 )(tap B A N D to select B1 through B4 ; on 30 m,
hold D I S P L A Y to select 1 0 . 0 or 1 0 . 1 )RP T

CW message repeat interval: 0 to 2 5 5 seconds

CAL

I NP

CW input device selection:
Hn d (hand key or external keying device)
P Dn (internal keyer, paddles normal)
P Dr (internal keyer, paddles reversed)

operating frequency cal (O P F), per-band(hold D I S P L A Y to select O S C for VFO test)

SI G

S-meter zero set: L x x , where x x = 3 0 -7 0
(hold D I S P L A Y for scale: Hx , where x = 2 -6 )NBnoise blanker mode: O FF, HI , L O

ATU

automatic antenna tuner mode (see KAT1 manual)

P Fn

programmable function (PFn) assignment;
sets up X I T [ P F n ] switch as a shortcut to a selected
menu entry. Set to NO R (normal) to use XIT.

IAB

iambic mode: A or B

A GC

AGC O N or O FF; no S-meter if O FF

4Tones are only available on the RIT, XIT, and ATTN switches; they areuseful when you have the LEDs turned off. When you hold D I S P L A Y , themenu parameter will flash A F if tones are enabled and NO R if disabled.

ELECRAFT

53

Calibration Functions

Operating Frequency Calibration and VFO Test (CAL)The FL x , Bx , C A L , and S I G menu entries are typically usedduring initial test and setup of the K1. Bx and C A L are also usedwhenever you plug in a different Filter module to allow the K1 todisplay the correct frequencies.

This menu entry is used to calibrate the operating frequency
display, or to align the VFO. (VFO test and alignment is covered indetail on page 38.)

Crystal Filter Bandwidth Selection (FLx)
The K1 provides three crystal filter bandwidths, FL1, 2, and 3,
which are selected using X F I L during normal operation. By default,
the filters are set to about 800, 400, and 250 Hz. You can changethese settings using the FL x menu entry.
To modify the bandwidth for a particular filter, enter the menu andscroll to FL x (where x is 1 , 2 , or 3 ). Use X F I L to change the menu
entry to the desired filter. Hold E D I T , then tap W P M + / W P M - toselect one of the available bandwidths, in Hz. The bandwidth
settings are approximate.
The BFO is not programmable. One setting of C20 on the RF board
is used for all filters (see page 40).
Band Assignment (Bx)This menu entry is used to tell the K1 firmware what bands yourFilter board covers, allowing the B A N D switch and VFO to display
the correct frequencies. You should set up B1 and B2 (as well as B3
and B4 if applicable), then do VFO calibration using C A L .
The Bx parameter can be set to any band from 1 . 8 to 2 8 . 0 MHz,corresponding to the components on the Filter board. Some ofthese bands may not available from Elecraft, but can still be used if
you obtain the necessary components.
On 30 meters, you have a choice of two different band edges,
corresponding to your selected VFO range (see page 12). HoldD I S P L A Y to select either 1 0 . 0 or 1 0 . 1 MHz.

To calibrate the operating frequency: Switch to the band to becalibrated and tune in a signal at a known frequency. Then selectC A L in the menu and hold E D I T . You'll see O P F briefly, then theoperating frequency will be displayed to 100 Hz. The last digit
flashes as a reminder that you're in calibration mode. Use W P M +and W P M - to set the reading to match the known frequency.
Note: Each band must be set independently since they use different
crystals on the Filter board.
To check the range of the VFO: After holding E D I T , hold D I S P L A Y
to switch to O S C . The display will then show you the MHz andkHz portion of the VFO frequency, alternating about once persecond. Turn the VFO pot all the way in both directions to checkthe range. Holding D I S P L A Y again will switch back to O P F(operating frequency calibration display).
S-Meter Calibration (SIG)
To check the S-meter zero setting, use D I S P L A Y to switch to Smeter mode, make sure the attenuator is OFF, and disconnect theantenna. With no signal, the S-meter should indicate 0 bars, or the
first bar may just be flickering on. If not, you can use the S I G
menu entry to change the L x x parameter. After each change to
L x x , hold E D I T to exit the menu and return to the S-meter display
to see the effect on the S-meter reading.
To check the S-meter full-scale setting, re-connect the antenna andtune in a very strong signal. If the S-meter's reading appears to be
too low or too high for the given signal strength, use the S I G menu
entry to change the Hx parameter. (To get to the Hx parameter,hold D I S P L A Y while the L x x parameter is displayed.) Reducing theHx parameter value will increase the S-meter reading.

ELECRAFT

54

Basic K1 Operation

Transmitter Setup

Self-Test: A number of tests are done at power-up. If you see anerror message (such as E4 2 ), refer to Troubleshooting.

Display Mode: During transmit the LCD normally shows abargraph (1 bar per watt). If you select supply voltage display mode
(using D I S P L A Y ), the power supply or battery voltage will beshown, flashing slowly. In TUNE mode, power is shown in watts(see below). SWR can be displayed if the KAT1 ATU is installed.

Band and Frequency Display: When you turn on the K1 or tap
B A N D , the current band and operating frequency will be displayed.

For example, if the last band used was 40 meters and the VFO was
set to 7025.3 kHz, the LCD would show 7 , then 0 2 5 , and finally
25.3.
Changing Bands: To change bands, tap B A N D quickly two or
more times.

Receiver Setup
Display Mode: Holding D I S P L A Y alternates between threereceive-mode displays: frequency (default), S-meter, andvoltmeter. For normal operation, use frequency or S-meter mode.
(In S-meter mode, the frequency is re-displayed automaticallywhenever the VFO is moved.)
AF GAIN: Adjust the AF GAIN control for comfortable headphoneor speaker volume. The sidetone volume can be set higher or lower
in relation to receiver audio using the S T L menu entry.
Crystal Filter Selection: Filter FL1 (usually the widest filter) is
selected on power-up. Holding X F I L cycles through the filters. Usenarrower filters to reduce interference from nearby stations.
Attenuator: Holding A T T N switches in about 14 dB of attenuation.
This may be useful if extremely strong signals are causing receiver
overload. The receiver has sufficient sensitivity to allow theattenuator to be left in at all times, if necessary. If you turn theattenuator on when the display is in S-meter mode, an extra bar isadded to the S-meter display to compensate. (Note: You can disable
LEDs to save current using the L ED menu entry.)

Setting Power Output: Approximate power output can be set
using the O UT menu entry (0 . 1 to 7 . 0 watts). Anytime youchange the power level or change bands, you’ll see power start out
near zero, then go up while you send the first few characters of
CW. This is due to the transmitter’s ALC (automatic level
control). Caution: When working into non-50-ohm loads, thepower display may not be accurate.
TUNE Mode: To put the transmitter into TUNE mode (keydown), press the W P M + and W P M - switches simultaneously. At 5
watts, the display would show P 5 . 0 . (It is normal for this number
to vary over as much as several tenths of a watt.) While in TUNE
mode, you can change power output using W P M + and W P M - .
Keyer Test Mode: It is possible to completely disable thetransmitter to do keyer or message buffer testing (page 55).
QSK Delay and Sidetone: The QSK delay is set with the T - R
menu entry. Sidetone volume and pitch are set using the S T L and
S T P menu entries, respectively.
Transmit Offset: The transmit offset should be matched to yourselected sidetone pitch using C13 on the RF board. This is normallyaccomplished during alignment (page 47).
Transmit Frequency Limits: Some countries require transmit to
be disabled outside of specified amateur bands. Your K1 may include
such limits encoded in firmware. In this case, if you key thetransmitter with the VFO set outside the usable range, you’ll see
En d on the LCD.

ELECRAFT
RIT and XIT
RIT (receive incremental tuning) can be used to fine-tune the pitchof a received signal without affecting your transmit frequency. Thisis most often used when a station calls you off frequency. To turn
on RIT, tap R I T . The RIT LED (green) will turn on, and the LCD's
decimal point will flash slowly. You can then use the OFFSET
control to vary the receive frequency.
XIT works similarly to RIT, except that the transmit frequency isvaried with the offset control. For example, suppose a DX station
says to call "up". First, turn on R I T and use the OFFSET control tofind a clear spot above the DX station's frequency. Then turn on
XIT by holding X I T [ P F n ] .5 The XIT LED (orange) will turn on. If
you need to determine the transmit frequency when using XIT,
briefly turn on R I T , then switch back to X I T .
OFFSET Range: The range of the OFFSET control is determinedby the value of C7, in the VFO area of the RF board. A larger orsmaller value of C7 will increase or decrease the OFFSET range,
respectively.

Keying Device Selection
A single connector in the back is provided for your keyer paddle,
hand key, keyer, or computer. You must use a stereo (2-circuit)
plug, even if you use only a hand key or external keyer. This should
not affect the use of the keying device with other equipment, since
the middle contact on the plug (often called the "ring" contact) is
only used with keyer paddles.
Hand key or External Keying Device: To use a hand key,external keyer, computer, or external keying device, set I NP t o
Hn d using the menu. You can key the K1 externally at up to 70
WPM. Note: The K1's message memories can only be programmedusing a directly-connected keyer paddle.
5

If you have assigned the XIT [PFn] switch to another function using thePFn menu entry, you cannot use XIT.

55

Internal Keyer: To use a keyer paddle, use the menu to set I NP
t o P Dn or P Dr (normal or reverse paddle). With P Dn selected,
the "tip" contact on the stereo key jack is DOT and "ring" (themiddle contact) is DASH. P Dr is the reverse.

Keyer Setup
Keyer Speed: Use the W P M + and W P M - switches to select thedesired CW speed. The display will show the speed in WPM.
Tapping either switch quickly two or more times will cause thespeed to jump in 2 WPM increments.
Iambic Mode Selection: If you use a keyer paddle with two
mechanically-independent levers, you can use iambic keying,
meaning that both the DOT and DASH paddles can be pressed at
the same time to generate a repeating DOT-DASH or DASH-DOT
pattern. With practice, this can improve sending efficiency. TheI A B menu entry allows you to select from two Iambic modes: A or
B. If you're not sure which to use, select mode A (the default)
which has more forgiving timing characteristics. Mode A is similar
to mode A of the Curtis keyer IC; mode B is similar to Super CMOS
Keyer III mode B.

Keyer Test ModeAt times you may want to disable the transmitter completely sothat you can practice recording messages or just sending code withthe keyer. The K1 has a built-in Keyer Test mode for this.
To activate keyer test mode, first select the O UT menu entry andhold E D I T to display the power output level. Next, hold D I S P L A Y .
The power output parameter will change to P = 0 , indicating thatthe transmitter is disabled. To restore the original power levelsetting, hold D I S P L A Y again.
Note: Turning power to the K1 off and back on cancels keyer test
mode and restores the original power level.

ELECRAFT

56

Recording and Playing Messages
The K1 provides two CW message memories of 90 bytes each. CW
messages can only be recorded using a keyer paddle connected
directly to the K1's key jack. Set I NP to P Dn or P Dr . Messages are
stored in EEPROM, so they won't be lost when power is turned off.
To Record a Message: Hold R E C , and when prompted with 1 - 2 ,tap either 1 or 2 . The display will then show REC 90, indicatingthat 90 bytes of storage are available in this message buffer. This
number will count down toward 0 as long as you are sending.
Whenever you stop sending completely, up to two standard-length
word spaces will be inserted. To stop recording, tap M S G . If you do
this before starting to send, the original message contents will not
be lost.
To Play a Message: Tap M S G , then select a message by tapping
either 1 or 2 . Message play can be canceled at any time by hitting
M S G again or by tapping the keyer paddle. You can also change thekeyer speed while messages are playing, using W P M + and W P M - asusual.
Keyer Test Mode: To play back messages without transmitting,use keyer test mode (page 55). In this mode, you'll see P = 0 on the
LCD during message play, rather than the transmit bargraph.

Using Auto-Repeat
Either message memory can be auto-repeated when played, which isuseful when calling CQ on a quiet band or during contests.
Sometimes a band will be open but will "sound" dead, simply because
no one is calling CQ at that moment. This is a great time to let
auto-repeat do the work.
To use Auto-Repeat: Tap M S G as usual, but then hold either 1 or
2 . The message will then play back continuously until you tap M S Gagain or hit your key or paddle. You'll see RP T on the display inbetween message transmissions.

Setting the Auto-Repeat Interval: The length of the pause
between messages during auto-repeat can be programmed using the
RP T menu entry (0 -2 5 5 sec.). Long delays are useful for beacons.
Using RIT During Message Repeat: You can use RIT (if it isturned on) to listen above and below your receive frequency
between calls. This is useful when stations call you off-frequency.

QRP Operating Tips
Antennas: When you're using low power, a good antenna andground system can make a big difference. In general, antennas
should be mounted as high off the ground as possible, and resonantor multi-element antennas will be the most effective. An excellent
choice for light-weight, multi-band portable use is a long, end-fed
wire, used in conjunction with two or more ground radials and anantenna tuner. There are many references on antennas available,
including the ARRL Antenna Handbook.
QRP Frequencies: Low-power enthusiasts can be found at certain"watering holes" on each band, listed below (MHz). An asterisk (*)
indicates European or alternative QRP frequencies.
80 m: 3.560
30 m: 10.106 (*10.116)
17 m: 18.096

40 m: 7.040 (*7.030)
20 m: 14.060
15 m: 21.060

Calling and Listening: Calling CQ with low power may befrustrating unless you have a good antenna. Usually, you'll spend far
more time listening. Keep transmissions short, especially whenworking other QRP stations, which will often be at or even below
the noise level. Narrower filters (< 500 Hz) and slower code speeds
should be used when conditions are marginal.
Contests: Both general interest and QRP-only contests provide agreat way to work new states or countries. The K1, with its low
current drain and compact size, is particularly well-suited to outdoor
events such as Field Day and QRP To The Field.

ELECRAFT

57

Advanced Operating Features

K1 Options

Programmable Function Switch (XIT [PFn])

Four- and Two-Band Filter Modules (KFL1-4, -2)

By default, the X I T [ P F n ] switch turns XIT on and off.
Alternatively, this switch can be set up as a direct edit shortcut toany menu entry. To program the switch function, enter the menu
and scroll to P Fn , then change the parameter to the desired menu
entry. Setting it to NO R (normal) assigns the switch to XIT.

The KFL1-4 and KFL1-2 options provide additional bands of yourchoice, allowing you to select the best combination of bands forhome use, field trips or specific operating events. The KFL1-4
includes 40, 30, 20, and either 17 or 15 meters.

Spotting
The S T P menu entry can be used to "spot," or match the pitch ofreceived signals, so that you'll be exactly on frequency when you
transmit. To spot a signal, select the S T P menu entry, hold E D I T ,then adjust the VFO until the received signal pitch matches thesidetone pitch. The received signal may seem to disappear when thepitch is exactly matched. You can assign S T P to theprogrammable function switch if you don’t use XIT (see above).
X I T [ P F n ] will then activate the spot signal.

AGC Control
Some operators prefer to turn AGC off and use manual gain control
under certain weak-signal conditions. To turn AGC off, use theA G C menu entry. The attenuator may help with strong signals.

Checking the Firmware Revision
Hold any switch on power-up to display the revision (e.g. 1 0 8 ).

Resetting to Factory Defaults (requires rev. 108 or higher)
Reset to defaults takes two steps. Step 1: Hold B A N D and M E N U
together on power-up, releasing the switches after the LED test.
You should see E0 9 . Step 2: Turn power off and back on again;
you should see E1 0 . You’ll then need to re-do VFO calibration, etc.

Wide-Range Tilt Stand (KTS1)
When hiking or camping, you may find that there's no table orother smooth surface on which to operate a transceiver. The KTS1
solves this problem by allowing you to rest the K1 on nearly any
rough surface (rock, dirt, etc.) and tilt the display upwards to theideal viewing angle. It also keeps antenna and power connections
away from the ground, and provides a mounting point for a keyer
paddle. (Refer to our web site for information on custom paddles.)Noise Blanker (KNB1)
The KNB1 is effective in reducing pulse-type noise, such as thatfrom power poles or automobile ignition systems.

Automatic Antenna Tuner (KAT1)
If the KAT1 internal automatic antenna tuner is installed, you canconnect coax-fed or random-length wire antennas directly to theK1. An inexpensive home-made balun can be used with balancedlines. In most cases the tuner will allow you to match one antenna
on all bands. Once you've tuned up an antenna, the tuner's L and C
settings will be recalled instantly when the band is changed.

Internal Battery (KBT1)
The KBT1 includes an 8-AA-cell socket and a replacement top
cover with a quick-access battery door. Any cell type may be used.

ELECRAFT

58

12. Circuit Details
While reading this section, refer to the Block Diagram (AppendixB) and schematics (Appendix C).

Overview
The K1 is a compact, high-efficiency CW transceiver capable ofoperating over a wide range of frequencies. The two (or four) bandsof operation are determined by a single plug-in filter module,
allowing the builder to swap in a different set of bands if desired.
The firmware will recognize whether a two- or four-band board isinstalled.
The filter module includes the band-pass filters and crystals for theK1's pre-mix conversion scheme, in which a low-frequency (~3MHz) VFO is subtracted from a high-frequency crystal oscillator to
produce a "pre-mixed" injection frequency for the transmit andreceive mixers. Because of the VFO's low operating frequency,
stability is excellent. An analog VFO is used, resulting in a lower
noise floor than most synthesized transceivers. The filter board
also has RF band-pass and low-pass filters for each band.
The receiver is a single-conversion superhet, using downconversion to a low intermediate frequency (I.F.) of about 4.915
MHz. Down-conversion minimizes complexity and receive-chain
noise, while the low I.F. allows good CW selectivity with a 4-pole
crystal filter. The use of active mixers keeps current consumption
low, compatible with portable operation.
There are three stages of transmitter amplification. Maximum
power output from the final stage (class C) is about 5 to 7 watts,
depending on the band and supply voltage. The T-R circuitry is all

solid-state (no relays), resulting in smooth, fast QSK.
A low-power microcontroller (MCU) on the front-panel board isused to control the transceiver and handle user interface elements,
such as the display and switches. A second, smaller microcontroller,
the I/O controller (IOC), acts as a driver for the filter andattenuator relays. The IOC is controlled by the main MCU via a
one-line network, the auxBus. Option microcontrollers (i.e., on thenoise blanker and antenna tuner) also communicate via the auxBus.

Front Panel Board
Microcontroller (MCU) U1 is used to control all K1 functions, anddoubles as the driver for the LCD, DS1. U1 runs at just below 4
MHz. The crystal, X1, is intentionally kept under 4 MHz (by usinglarge oscillator capacitors), so that any internally-generated bandedge signals will be below the bottom edge of the band.
The LCD segments are driven with 50% duty cycle square waves toensure that the average DC voltage on each segment is 0 volts. The
LCD backplane (pin 24) is also driven by a low-frequency squarewave. To turn on a segment, it must be driven 180-degrees out ofphase with the backplane. In-phase segments remain off.
The MCU has a number of miscellaneous functions. It reads thestates of the switches (S1-S6) by periodically making the associatedLCD drive lines into inputs. The VFO signal is amplified by Q1,then counted at MCU pin 6 (RA4). Pin 3 (RA1) is made an A-to-D(analog-to-digital) input to read the battery voltage, or an output toturn the ATTN LED on or off. Pin 4 (RA2) drives to 6 V or 0 V toturn on the RIT or XIT LEDs, respectively (both part of D1), by

ELECRAFT
virtue of an intermediate voltage supplied by op-amp U5A. To turnboth elements of D1 off, pin 4 is made an input.
The states of the DOT and DASH lines are sampled on analog input
RA3 (pin 5). If both DOT and DASH are open, the voltage at RA3
will be about 6 V. If both are closed, the voltage will be 0 V. If only
one paddle is closed, an intermediate voltage results, either 2 V or 4
V. (See RF board, sheet 2.)
Q2 defeats the RIT/XIT offset when its gate voltage is at 6 V,
since its low drain-source resistance forces a fixed 3 V to appear at
the wiper of the offset pot, R3.
U2 and U3 are controlled by the SDA (data) and SCL (clock) lines,
using the industry-standard I2C protocol. U2 is a dual-output D-toA converter that controls the power level and generates audio
tones. When tones are not being generated, the tone output is used
to set the crystal filter bandwidth. U3 is a 512-byte EEPROM,
which stores all K1 operating parameters and CW messages.
VFO pot R1 is physically part of the front panel assembly, but its
wiper voltage (0-6 V) is routed to the RF board via J1. R19, locatedbetween the wiper and the high end of the pot, improves tuning
linearity.

Filter Board
Note: This section applies to the 2-band filter module (KFL1-2).
For details on the four-band module, refer to the KFL1-4 manual.
L1-L4 and associated capacitors form two band-pass filters, one forthe premix signal on each band. There are also crystals for eachband (X1, X2). For example, on 40 m (7.000 MHz), the premixer(U7, RF board) mixes a 3.085-MHz signal from the VFO with a
15.000 MHz crystal oscillator to obtain a difference signal at
11.915 MHz. There is also a sum frequency, 18.085 MHz, which is
rejected by the band-pass filter. The 11.915 MHz signal is routed to
the RF board at P1 pin 6.

59
L5-L8 and associated capacitors form two RF bandpass filters, one
for each band. T-R switching circuits on the RF board place thesefilters in either the receive or transmit path. L9-L12 and associatedcapacitors form the two low-pass filters.
All filters and the two crystals are switched by latching relays K1K3. Microcontroller U1 pulses the relay coils bidirectionally toswitch them on or off. The reset condition of each relay selects
band 1. Latching relays are only energized when switched between
set and reset, so they consume no power during normal operation.

RF Board
VFO (Sheet 1)
Q8 is used in a varactor-tuned Colpitts VFO. The VFO tunes"backward." For example, its frequency is about 3.080 MHz when
the operating frequency is 7.000 MHz, and 2.930 MHz when theoperating frequency is 7.150 MHz. This is due to the fact that the
VFO is subtracted from the crystal oscillator in the premixer (U7).
The use of varactor diodes (electronic tuning) results in acompromise between circuit complexity, tuning range, and stability.
While VFO drift can never be eliminated entirely, steps were taken
to minimize it.
First, the VFO supply voltage is double-regulated (explained in thenext paragraph). This improves stability by guaranteeing a very
stable voltage reference for the varactor diodes. Since thetransmitter circuits run from a different regulator, and since the
VFO is also well-buffered from the transmitter, there is virtually no
VFO frequency shift or chirp on key down over the full power
output range (0.1-7 watts). Second, temperature-compensation
techniques are used in the VFO itself, including careful selection of
capacitor types. The inductor used has a low temperature
coefficient, and its turns are adjusted to select the desired range,
which eliminates drift-prone trimmer capacitors.

ELECRAFT

60
Q9 isolates the VFO from noise pickup on the frequency counterline. U5 and U6 double-regulate the VFO supply voltage for
improved stability. Since U5 is a low-dropout 8-volt regulator, theK1's supply voltage can drop to as low as about 8.5 V without
affecting the VFO frequency. U6 is a 6.0-volt regulator with a very
tight tolerance of 2.5%.

U4 amplifies the received audio signal and sidetone to headphone or
speaker level. The AF GAIN control is located on the front panel,
but is electrically connected between Q11 and U4 at the AF1 andAF2 points.

Premixer U7 mixes the VFO with one of the crystals on the Filter
board.

In receive mode, the AGC signal is routed onto the RF/SMTR line,
which is then sampled by an A-to-D input on the MCU (U1, front
panel). Q1 is used to connect or disconnect the AGC signal fromthe RF/SMTR line.

Receiver (Sheet 1)

Transmitter (Sheet 2)

U1 is a double-balanced receive mixer, which provides an excellent
noise figure at low current drain. If input levels are too high, anattenuator can be switched in via K1. RFC9 (across K1) suppresses
attenuator on/off switching noise that might otherwise be audible.

To vary the power output, JFET Q5 and PIN diode D18 control
the amount of premix signal input to the transmit mixer, U8. The
DC control voltage at the drain of Q5 is set by the MCU (U1, front
panel). ALC (automatic level control) is implemented in firmware.
During keying, the ALC determines what DC voltage is needed to
get to the requested power level, as well as what voltage
corresponds to zero output. As you key the transmitter, the control
voltage alternates between these two levels so that that the keying
waveform can be effectively shaped by R10 and C59.

Emitter-follower Q3 provides some power gain while providing a
low driving impedance for the crystal filter (X1-X4). The crystal
filter has variable bandwidth, by virtue of varactor diodes D6-D8.
T2 steps up the crystal filter output to match the 1500-ohm input
impedance of the product detector/BFO, U2. The BFO is mixed
with the I.F. to produce an audio signal.
U3 amplifies the audio signal enough to drive the audio-derived
AGC detector, D2. R21 and C18 remove high-frequency hiss.
D2 is DC-biased just below the level needed to turn on darlington
transistor Q2. When a signal is present, Q2 will turn on in
proportion to the signal amplitude, pulling the AGC line down fromits nominal 1.2 V to as low as 0.6 V. The AGC line is connected tothe input bias pins of both U1 and U2, so that the gain of bothmixers is reduced as signal strength increases. R1 limits the gain
reduction at U1, so most of the AGC action is due to U2, which
minimizes the chance of front-end overload when AGC is activated.
Only signals in the passband of the crystal filter can cause AGC in
any case, so the AGC line stays at about 1.2 V most of the time.
Q10 and Q11 are shunt and series mute devices, respectively. Bothare required due to the large amount of audio gain in the receiver.

Video amplifier U9 buffers and amplifies the TX mixer output. Q14
keeps U9 fully turned off during receive. The low-level transmit
signal is passed through the RF band-pass filter on the Filter board
via J7.
D9-D13 form a fast, high-isolation T-R switch that allows theappropriate RF band-pass filter to be shared between receive andtransmit. On transmit the signal is routed through D9 to the drivertransistor, Q6. On receive, D10, 11, and 12 are turned on,
bypassing the transmit stages.
Q7 is the class-C final amplifier. It operates at a nominal collector
impedance of 12.5 ohms, which is stepped up to 50 ohms by T4.
Q7's output is filtered by one of the low-pass filters on the Filter
board, with signals routed through J8. RF detector diode D15
samples some of the RF output voltage to provide a power output
indication. If the KAT1 antenna tuner is installed, its SWR
bridge/wattmeter output takes over from D15, via pin 5 of J8.

Appendix A
PICTUREK1 Packing Box Parts List
Designators

Revised 11-30-2000

Misc.

RF PC board

E100094

1

B1

Left side panel

E100097L

1

B2

Right side panel

E100097R

1

B3

Front panel, silkscreened

E100096SS

1

B4

Bottom cover, silkscreened

E100098SS

1

B5

Top coverE1000991Bag, Misc.

Hardware and miscellaneous components

E8500241

Bag, Wire

Wire and coax

E8500231

Bag, Filter Board

Components for 2 or 4-band Filter PC board

KFL1-2 or KFL1-4

1Bag, Per-Band Components

Additional Filter board components for two selectedbands (2-band K1 kit only).
Elecraft order numbers shown at right.

K1B80, K1B40,
K1B30, K1B20,
K1B17, K1B15

2

Bag, Front Panel Board

Components for Front panel PC board

E8500211

Bag, RF Board

Components for RF PC board

E8500201

HW (in envelope)

Thermal insulator, TO220; for Q6, Q7 (RF BOARD)

E7000022

Description

Page 1

Part Number

QTY

Box

Appendix A
PICTUREK1 Packing Box Parts List
Designators

Revised 11-30-2000

Misc (in envelope)

Acrylic display bezel; for LCD (Front Panel)

E100108

1

Misc (in envelope)

Serial Number Label

E980024

1

SP1

Speaker, 8-ohm, 1 watt

E980032

1

KN1

Large knob, 1.25" dia, 0.25" shaft; Rogan #RB-67-3-M

E9800211

KN2, KN3

Small knob, 0.5" diam, 6mm shaft

E9800162

Description

Page 2

Part Number

QTY

Box

Appendix A
PICTURE

K1 Front Panel Board Parts List
Designators

Description

Part Number

QTY

C1, C282 pF NPO disc; label: "82"E530038

2

C5, C6.01 µF, monolithic; label: "103"E5300092

C4.047 µF, monolithic; label: "473"

E530025

1

D1LED, dual, orange/green; LiteOn LTL-298WJ(Digikey 160-1037)

E570000

1

D2

LED, yellow; LiteOn LTL-4253 (Digikey 160-1133)

E570001

1

D3

Diode (not used at present)

DS13-character, 7-segment LCD(V.L. Electronics p/n VI-321-DP-RC-S-12)

E6000151J1

20 pin x 1 female socket

E620025

1Q1

2N4124 transistor, TO-92 plastic

E580006

1Q2

2N7000 transistor, TO-92 plastic

E580002

1

Page 10

Front PanelNOTE: Many of the resistors are supplied attached to strips of tape in assembly order, however some are also supplied loose
Be sure to check the color codes of all resistors during assembly to be sure you're installing the correct part.

Appendix A
PICTURE

K1 Front Panel Board Parts List
Designators

Description

Part Number

QTY

S1-S6

Switch, push button

E640005

6

U1

PIC16C77MCU, programmed ("K1"), 40 pins

E610005

1

U2
U3
U5

MAX518BCPA; Dual D/A converter, 8 pins
Alt: MAX518ACPA
24LC04B/P; EEPROM, 8 pins (alternate: 24WC04P)
LM358, 8 pins

E600013
E600021
E600010

1
1
1

U4
X1
Misc.
Misc

ZR78L06C; Voltage regulator, 6V, 2.5% (Zetex);
TO-92 plastic, 3 pins
4.000 MHz crystal; HC-49, standard height
Front Panel PC board
40 pin DIP socket (for U1)

E600017
E660006
E100093
E620017

1
1
1
1

Misc

switch spacing tool (made from PCB material)

E980033

1Miscnylon washer, 0.75" O.D., 0.385" I.D. (Keystone #3227)

E700019

1

Misc
Misc

Keycap, rectangular, black
Keycap, square, black

E980000
E980009

5
1

Page 3

Front PanelAppendix A
PICTUREK1 RF Board Parts List
Designators

Description

Part Number

QTY

C14, C15, C16, C19, C22, C28,
C29, C51.001 µF, monolithic; label: "102"E5300018

C4, C6, C17, C18, C21, C23,
C25, C36, C37, C40, C43, C44,
C45, C47, C48, C49, C58, C60,
C64, C66, C72, C74, C75, C76.01 µF, monolithic; label: "103"E53000924

C24, C30, C32, C41, C50, C56,
C57, C61.047 µF, monolithic; label: "473"

E530025

8

C34, C46, C52, C55, C68, C70,
C71, C73

0.1 µF, monolithic; label: "104"E5300118C3

10 pF NPO mono or disc, 5%; label: "10"E530006

1

C65

22 pF NPO mono or disc, 5%; label: "22"E5300171

C7, C26, C27

39 pF NPO mono or disc, 5%; label: "39"E530036

3

C2

68 pF NPO mono or disc, 5%; label: "68"E530007

1

C8

82 pF NPO mono or disc, 5%; label: "82"E530038

1

C1

150 pF NPO mono or disc, 5%; label: "151"E530049

1

C38, C39, C42, C69

220 pF NPO mono or disc, 5%; label: "221"E5300424

C62, C63

330 pF NPO mono or disc, 5%; label: "331"E530043

2

C2A (alternate for C2)

120 pF polystyrene, axial leads, 5%; label: "120J"

E530070

1

C11, C121200 pF polystyrene, axial leads, 5%; label: "1200J"

E5300692

C53300 pF polystyrene, axial leads, 5%; label: "3300J"

E5300711

C31, C54, C67

2.2 µF electrolytic, 25V

E530023

3

C78

Electrolytic capacitor, supplied with 80-m band kit(2-band module only)

C33, C35, C59

10 µF electrolytic, 35V; low-profile (Digikey P922-ND)

E530045

3

C9, C10, C53

220 µF electrolytic, 25V (Digikey P6240-ND)

E530046

3

Page 10RFAppendix A
PICTUREK1 RF Board Parts List
Designators

Description

Part Number

QTY

C13, C20

Ceramic trimmer capacitor, 8-50pF

E530000

2

D2, D15

1N5711 Shottky diode, small glass pkg

E5600042

D5, D9-D14, D18

1N4007 PIN diode, large plastic pkg, black

E560001

8D19

1N4753 zener diode, 36 V, 1 watt

E560007

1

D1, D17

1N4148 switching diode, small glass pkg

E5600022

D16

SB530 Shottky diode, 5A, very large plastic pkg (black)(alternate: 1N5821)

E560003

1

D4

MV209

E560006

1

D3, D6, D7, D8

1SV149; TO-92 pkg

E560005

4

J6, J7, J88-pin 0.1" conn., female; Samtec SSW-108-01-G-S.

E620005

3

J1

Supplied with noise blanker option (KNB1)

E6200050J4

2.1 mm DC barrel connector

E620026

1J5

BNC jack

E620020

1Page 2RF

Appendix A
PICTUREK1 RF Board Parts List
Designators

Description

Part Number

QTY

Keyer Jack, threaded bushing, Stereo, vertical mount
J3

E6200271

E620028

1

J2

Headphone jack, non-threaded, Stereo, with switch,horizontal mountJ9, J102-pin, pads only (coax soldered to connections--see text)

K1

Latching Relay, 5V; in plastic tube

E640001

1

L1

T50-6; Toroid (yellow), approx. 4.4µH; 33 turns

E680010

1

L2

FT37-43; Toroid (gray); 16 turns

E680003

1

T1

FT37-43; Toroid (GRAY), 4:20, receiver mixer input

E680003

1

T2

FT37-43; Toroid (GRAY), 5:20, product detector input

E680003

1

T3

FT37-43; Toroid (GRAY), 12:4, driver to final

E680003

1

T4

FT50-43; Toroid (GRAY, larger), 5 turns bifilar

E6800081

RFC8

Supplied with 80-m band kit (2-band module only)

RFC9

15 µH RF choke; min. solenoidal; color code: brn-grn-black

E6900121

RFC2, RFC5

22 µH RF choke; soleniodal, color code: red-red-black

E690000

2

RFC1

33 µH RF choke; soleniodal, color code: orange-orangeblack (NOTE: orange bands may appear brown)

E6900071

RFC3, RFC4, RFC6, RFC7

100 µH RF choke; soleniodal,
color code: brown-black-brown

E690004

4

Page 300RFAppendix A
PICTUREK1 RF Board Parts List
Designators

Description

P1
P2
P3

20 x 1 ,male, RA; 20 pin male, right angle. To Front Panel,
J12 pin, male, 0.1" conn with locking ramp; for speaker
3 pin, male, 0.1" conn.; RF detector selectQ6

2SC5739 or 2SC2166; driver

Q7
Q5, Q8, Q11Q9Q3, Q14
Q1, Q10
Q2

Part Number

QTY

E620029
E620024
E620007

1
1
1

E5800

1

2SC1969; PA (Power Amp)
J309, JFET, TO-92
2N3906, PNP, TO-92
2N4124, NPN, TO-92
2N7000, MOSFET, TO-92
MPSA14, NPN Darlington, TO-92

E580008
E580009
E580000
E580006
E580002
E58001113
1Q4

ZVN4424A, MOSFET, Hi-V; Thinner TO-92 Style

E5800051

R37

226 Ω, 1/4W, 1%; color code: red-red-blue-black

E5000331R36

1.50 k, 1/4W, 1%; color code: brown-green-black-brown

E500034

1

R3
R23
R30
R15
R22, R31, R32
R16, R18
R11
R17, R35
R29, R38

8.25 k, 1/4W, 1%; color code: gray-red-green-brown
1.5 Ω, 1/4W, 5%; color code: brown-green-gold
3.3 Ω, 1/4W, 5%; color code: orange-orange-gold
10 Ω, 1/4W, 5%; color code: brown-black-black
33 Ω, 1/4W, 5%; color code: orange-orange-black
75 Ω, 1/4W, 5%; color code: violet-green-black82 Ω, 1/4W, 5%; color code: gray-red-black
120 Ω, 1/4W, 5%; color code: brown-red-brown
270 Ω, 1/4W, 5%; color code: red-violet-brown

E500065
E500044
E500064
E500054
E500036
E500037
E500038
E500022
E500039

1
1
1
1
3
2
1
2
2

Page 42
2
1

RFAppendix A
PICTUREK1 RF Board Parts List
Designators

Description

Part Number

QTY

R10, R33
R7
R12, R28
R1, R26, R27, R39
R5, R6, R9, R14, R21, R24
R4
R20
R19
R2, R25, R34
R13

470 Ω, 1/4W, 5%; color code: yellow-violet-brown
680 Ω, 1/4W, 5%; color code: blue-gray-brown
820 Ω, 1/4W, 5%; color code: gray-red-brown
1.8 k, 1/4W, 5%; color code: brown-gray-red
2.7 k, 1/4W, 5%; color code: red-violet-red
5.6 k, 1/4W, 5%; color code: green-blue-red
20 k, 1/4W, 5%; color code: red-black-orange
39 k, 1/4W, 5%; color code: orange-white-orange
100 k, 1/4W, 5%; color code: brown-black-yellow
2.2 M, 1/4W, 5%; color code: red-red-green

E500003
E500040
E500001
E500004
E500005
E500007
E500041
E500042
E500006
E500043

2
1
2
4
6
1
1
1
3
1

RP1, RP2

100 k SIP resistor pack, 8 pins, 4 resistors
p/n 8A3104G (alt: 77083104, L83C104, etc.)

E510018

2

RP4, RP5

3.9 k SIP resistor pack, 6 pins, 3 resistors
p/n 6A3392G (alt: 77063392, L63C392, etc.)

E5100082

RP6

27 k SIP resistor pack, 6 pins, 3 resistors
p/n 6A3273G (alt: 77063273, L63C273, etc.)

E510009

1

RP3

47 k SIP resistor pack, 10 pins, 5 resistors
p/n 10A3473G (alt: 770103473, L103C473, etc.)

E5100071

U5LM2930T-8, 8-volt regulator; TO-220 package

E600018

1

Page 5RF

Appendix A
PICTUREK1 RF Board Parts List
Designators

Description

Part Number

QTY

U4

LM380N-8, 8 pin DIP, AF amplifier

E600019

1

U3LM386N-1, 8 pin DIP, AF amplifier

E6000221U9LT1252, 8 pin DIP, VFO Buffer; TX Buffer

E600020

1

U1, U2, U7, U8

SA602AN, 8 pin DIP, TX Mixer; Prod. Detector
Alt: SA/NE612AN

E600006

4

U6

ZR78L06C, 6-volt reg., 2.5%; TO-92 package, 3 pins

E6000171

W1

Jumper, RG174 coax, From J9 to J10; see text

X1-X6

4.9152MHz Crystal; "ECS V4.9136" or similar.
Filter/BFO Xtals; Parallel mode, matched, HC-49

E660000

6

S1

DPDT Power Switch

E640006

1

S2

Miniature DPDT slide switch

E640009

1MISC

2-pin shorting jumper for use at P3 (RF detector select)

E620055

1MISC

Keycap, rectangular, for S1 (p/n TAC-BLK)

E9800231

HW#4, washer, nylon;
Washer, nylon, 0.375" diameter (For VFO inductor)

E700035

2

HW#4-32, nut, nylon; nut, nylon (For VFO inductor)

E7000211

HW

4-32,screw, nylon x 1/2"
screw, pan head, nylon (For VFO inductor)

E700022

1

Page 60RFAll capacitors are NPO disc or monolithic, 5% 0.2" lead spacing. Values are in pF.

** NOTE: The 80-meter band
kit also includes 10 µF
electolytic capacitor C78 thatis installed on the RF board.

Appendix A
PICTUREK1 Misc. Bag Parts List
Designators

Description

Part Number

QTY

HW

#4 int. tooth lockwasher (3 Spares)

E70001010HW#4 split lockwasher (4 Spares)

E70000416

HW

2-56,screw , 1/8", stainless steel, fillister head (2 spares)

E7000236HW
HW

2-D Fastener
4-40 nut, Steel-zinc (2 spares)

E100078
E70001189HW

4-40 screw, 1/4" Panhead phillips, steel-zinc

E7000051

HW

4-40 screw, 3/8" Panhead phillips, steel-zinc

E7000361

HW

4-40 screw, 3/16" Panhead phillips, black (5 spares)

E70001525

HW

4-40 screw, 5/16" Flathead phillips (undercut), BLK(2 spares)

E7000277HW
HW

4-40 screw, 3/16" Flathead phillips (undercut), BLK(3 spares)
4-40 standoff, round, 1/4" long x 3/16 dia. (for FP board)

E700025
E70002616
1HW

4-40 male/female standoff, hex, 7/16" long x 3/16" dia.; RAF
4504-440-A (for Filter board)
E700017

3

HW

Shoulder washer, nylon, black (for PA transistor, Q7)

E700001

1

HW

Self-adhesive rubber foot (Digikey SJ5518-0-ND)

E700024

4

Misc

LCD spacer, 0.5 x 0.5 x 0.187", self-adhesive both sides

E700020

1HW#4 flat washer, steel-zinc (for speaker); one spare

E700044

5HW#4 washer, .047" thick, fiber, black (for speaker)

E700028

4

Page 1

Misc and Wire

Appendix A
PICTUREK1 Misc. Bag Parts List
Designators

Description

Part Number

QTY

SPK-J1

2 pin female conn. Housing, 0.1” spacing, locking ramp.
(for speaker)

E6200211

ACC-P12.1mm male conn. (mates with DC power jack)

E620032

1

ACC-P2
Misc

Stereo 1/8” phone plug(for key, keyer, paddle, computer, or other keying device)
Female crimp pins for SPK-J1

E620033
E620022

1
2

Misc

Plastic tuning tool, p/n MARS-12

E980012

1

Misc

Allen wrench, 5/64", long handled (for large knob)

E980004

1

Misc

Allen wrench, .05", short handled (for small knobs)

E980008

1

Appendix A

K1 Wire Bag Parts List

PICTURE

Designators

Description

Part Number

QTY
(ft)

Misc

#26 Red Enamel Wire (for toroids)

E76000214

Misc#26 Green Enamel Wire (for toroids)

E760004

4

Misc#22 Dual-conductor wire (for speaker)

E7600121

Misc#24 solid-conductor hookup wire, insulated, green

E760008

1

Misc

Coax, RG174 (for jumper from J9 to J10, RF board)

E760010

0.5

Page 2

Misc and Wire

Transistors
2SC5739
2SC1969

2N3906
ZN4424MPSA142N70002N4124

DiodesJ309

MV209
1SV149

C

A
S

G

D

E

B

C

D

S

C

A

G

C

A

C

BC E
A = Anode, C = CathodeIntegrated Circuits
PLASTIC DIPVOLTAGE REGULATORS(DUAL-INLINE PACKAGE)
1
2
3
4

LEDs

78L06

8
7
6
5

LM2930T

D1

D2

BOTTOM VIEW

BOTTOM VIEW

GND

COUNT PINS STARTING AT
PIN 1 AND GOING COUNTERCLOCKWISE (8-PIN DIP SHOWN)

NOTCH

NOTCH

OUT GND INCATHODE

GREEN ANODE

OUT

IN
GND

ANODE

ORANGE ANODE

Special Symbols
Elecraft= On bottom of PC board.

K1

B y W. Burdick

E.Swartz

Schematic Key

Rev.

A

Date

9/4/00Appendix B

Sht.

1 of 1

24

23

22

21

20

19

18

17

16

15

14

VFO
TuningCOM 3G 3F 3 A 3B 2G 2F 2 A 2B 1G 1F 1 A

3

2

1

A

A

A

DS1
F

LCD

G

E
D

B

F

C

E

G

B

F

C

E

D

DP

G

3

B
C

D

DP

Pushbutton Switches

3E 3D 3C 3DP 2E 2D 2C 2DP 1E 1D 1C 1B
1

2

3

4

5

6

7

8

9

VFO POT

R19
100K

2

cw

13

6B

1

ccw

R1
100K

10

11

First label corresponds to switch TAP,
second label corresponds to switch HOLD.

12

S1

R14
1K

BAND

WPM +

S4

DISPLAYFILTER

C4
.047
1

6A
RF/SMTR
DVM/ATTN

5

KEYIN
6T
6R/AUX
4.000MHz

X1
C2
82

15

20

RB6

RA1

RB5

RA2

RB4

RA3

RB3

RA4

RB2

RA5

RB1

RE0

RB0

RE1

VDD

RE2

VSS

VDD

RD7

VSS

RD6

OSC1

RD5

OSC2

RD4

RC0

RC7

RC1

RC6

RC2

RC5

RC3

RC4

RD0

RD3

RD1

RD2

6A

7

D/A Converter

25

1
2
3
4

OUTA

OUTB

GND

VDD

SCL

AD0

SDA

AD1

8

1

7

2

6

3

5

4

2N7000

VCC

A1

WP

A2

SCL

VSS

SDA

8
7
6
5

U4
ZR78L06C

.01

6A

82 µH

ccw

10K

cw

Offset
R5
10K

R2
10K

6T

AF2

C6
.01

DVM/ATTN470
D2
YELLOW (ATTN)

AF Gain

R6

R7

12.7K

1

2

3

4

5

6

7

8

9 10 11 12 13 14 15 16 17 18 19 20

1%

1%
7

+
-

ccw

12V

OUT
IN
GND

3.92K

AF1
cw

RF/SMTR

R13

OFFSET

R3
S

A0

2.7K

6A
RFC1, 2 =

G
Q2

R16

C5
POWER

XFIL/TONE

RFC2/OFFSET

24LC04SCL

COUNTERCounter Amp.

U3

MAX518

6A

21

R4
10K
D

REC

EEPROM

U2

SDA

6A

2N4124

MSG

S6

PF1

1K

6B

Q1

RIT

30

R10
100K

U5A
LM358

ATTEN

RP1

2

-

WPM -

S5

EDIT

S3

12V

R11
100K

8

VFO POT

R12
2.7K

ORANGE (XIT)

5

6A

MCU

3

+
4

3

6

6B

1

D1

8

35

MENU

1

4

U1
PIC16C77R9100K

GREEN (RIT)2

S2/OFFSET

KEYIN

C1
82

10

RA0

R15
1K

40

6R/AUX

22

RB7

RFC1

R8

MCLR

U5B

5
6

Elecraft
B y W. Burdick

E. Swartz

K1 Front Panel Board
Rev.

E

Date

1/15/02J1
To RF-P1

Appendix B

Sht.

1 of 1

-14 dB

C66
0.01

2

1

4

2

5

4

1

7

2

3

4

5

6

7

75

1

J10

R1

Q1
2N7000

G

Q2

D3

L1

1.0VDC(no signal)

U4
LM380N-8

3

IN2

V+

GND

OUT

6

3

8V

5

2

C64

4

IN1

V+

IN2

OUT

GND

GND

6R/AUX

G

C17
.01

Q11
J309

C72
.01

5

RP3
47K

6

8

1

4

2

5

1

PREMIX
6

7

C27
39

47K

1

2

3

4

5

6

7

8

J6

Q9

To FIL-P1
R6

R23
1.5 Ω

6B
6A

OFFSET

RFC6

C8

C30

100µH

82

.047

RF/SMTR
C34
0.1
C36

AF1

RP3

/AGC OFF

C26
39

Buffer

C68

4

2

V3

2N3906

220µF

1

XFIL/TONE

680

C4
.01

0.1
AF2

C42
220

To Rcv Mixer (via W1)

Premix3.080 MHz when RF = XX.000 MHz

AF Amp

D

12V_2

2.7K

10µF

S

U7
SA602

C25
.01

R7

5

C33

1N4148

C9
+

6

C12
1200

2.930 MHz when RF = XX.150 MHz

7

2.2M

D1

8

C10
+
220µF

8

NC BYPASS

+

C71
0.1

7

.01

R13
PD2

1

C18
.01

8

4

D17
1N4148

D4
MV209

2.7K

1200

AF2

2N7000

4

D

G2

G1

7

OUT
IN
GND

C35
10µF

12V

LM386N-1

IN1 BYPASS

R15
10

0.1

R21
2.7K

U3

RP2
100K

LM2930T-8

6B

2.2µF

C63
330

U5

8V

C40
.01

VFO POT

C70
0.1

RP2
100K

S

C11

3

12V

C73

R5

G

COUNTER

+

D

KEYIN

C54

R2
100K

U6

V+

3300

C7
39

4.4 µHAF Preamp/Mute

.047

C5

1%

22

J9
Q8
J309

6B

7

C65

Product Det./BFO

Low-Dropout
8V Regulator

ZR78L06C

6R/AUX

8.25K

47K

7

C20 5 0

C41
.047

POWER

8

1SV149* * 6C28

RP3

R3

6

C67
2.2µF

OUT
IN
GND

VFO

6T

9

G

3

6V Reg.

6B

C6
.01

2

RP3
47K

6T

VFO POT
1

RP2
100K

RF/SMTRMPSA14

PD1

V-

D8

+

C31
2.2µF

5

2

X5
4.915 MHz** Use 120 pF at C2 for ~150 kHz range

S

10

PD2

4

RFC1
33 µH

1N5711NOT USED

C32

4

Crystal Filter

must be removed when
* C22
the noise blanker is installedD

6R/AUX

D2

6

2

D7

27K

+

RP2
100K

V+

1

2

RP6

AGC

8

1

1SV149

1

5

SA602

3

AGC (1.2VDC, no signal)/AGC OFF

1

D6

2.7K

Noise Blanker

2

1.8K

S

5:20, FT37-43
C38
220

X4

6

C61
.047

U2

C23
.01

6R/AUX

Q10

R14

J1

Premix

PD1

RP1
X3

4

T2

C37
.01

2

8

C19
.001

R18

5

RP1
X2

2

X1

6A

3

RP6
3

6

1

4

27K

.001

C39
220

XFIL/TONE

R17
120

RP1 7
RP1

C21
.01

RP6 5

V3

R16
75

*

6

C22

AF1

4

K1

100K

8

+

7

3

8

1

6R/AUX

.047
8
V+

3

9

2

4:20, FT37-43

RCV RF

C24

U1
SA602

T1

RFC9
10 µH

XFIL/TONE

Q3
2N4124

6A

Receive Mixer

Attenuator

3

C74
.01

1

RP3
47K

2

C69
220pF

2

.01
1

2

3

4

5

6

7

8

9 10 11 12 13 14 15 16 17 18 19 20

Elecraft
P1

J2
Headphones,
Ext. Speaker

P2
Int. Speaker

To FP-J1

K1 RF Board

B y W. Burdick

E.Swartz

Rev.

G

Date

Sht.

1/5/02

Appendix B

1 of 2

C45
.01
RFC4
100µH

6R_2

1
K1
(ATTN Relay)

D10
1N4007

10

6A

C47
.01

D13

1N4007

D11

R25

L2

2

3

4

5

6

7

8

1N4007
RFC3

J7

R4

C48
.01

+

D5

C78

R34

TR2

1

D14

R33

1N4007

470

R9

**

C53
220µF

12V_2

LT1252
7
+

6

-

4

RP4

6A

4

2

C16

C76
.01

4

V+

1

MIX
V6

7

R32

33

33

Q7
2SC1969

Key/Keyer/Paddle

12V DCAux 12 V

-

+

J4

POWER

D

D18
1N4007

S

Q5
J309

6A

2

RP5
3.9K

PRE

Transmit Attenuator

RP5

RP5

PREMIX
1

D16
SB530

/DOT

C14
.001

G

C28
.001

/DASH

470

ATTN
R35
120

C29
.001

R10

+

C58
.01

3

C3
10

X6

.001

.001

2

5

SA612

3

3.9K

5

4

3.9K

ON
6

12V
R19
39K

KEYIN

OFF

S1

R20
20K

Power

OSC

Q14
2N4124
RFC2
R39

C15

8

U8

R11
82

1

R31

C60
.01

C56
.047

.001

5

3.9K

C1 1 5 0

PA

10µF

OFS TEST

C51

6

RP4

*

If the KAT1 ATU is installed, jumper P3 pins 2-3.
If not, jumper P3 pins 1-2.

J3

C59

S2

RP4
3.9K

R12
820

4

P3
Det
* RF
SourceRF Output Detector
0.1

R30
3.3 Ω

6T

3

3.9K

3

C52

Driver

+

C57
.047

36V

Q6

OPER
U9

T4

R37
226Ω
1%

C43
.01

Transmit Mixer/Osc.

RFC8

Buffer

4
T3

R29
270

12V

2

3

2

2SC2166 or 2SC5739

install a jumper at RFC8.

BUF

1

D19

DRV

3

R28
820

is supplied with the** RFC880-m band kit. If 80 m is not used,

1%

1N4753

2

6R_2

C55
0.1

.01

TR1

R36
1.5K

1N5711

RF/SMTR12V

C78 is supplied withthe 80-m band kit

C44

1N4007

8

D15

100K

C50
.047

7

RFD

5.6K

T-R Switch
RFC5
22µH

33

6

Q4
ZVN4424ARCV RF

R22

5

J5
Ant.

6T

2.7K

4

6R_2

G

C46
0.1

R38
270

3

D

S

100µH

D9
1N4007

To FIL-P2

TR3

R24
2.7K

2

PA

47µH

100K

1

2

1

BPF

To FIL-P3

ANT

R27
1.8K

6R_2
R26
1.8K

J8

C49
.01

D12

1

RFC7
100µH

C75
.01

3

6R/AUX

22 µH

4.915 MHz

C13
50

K1 RF Board

Elecraft

C62
330

B y W. Burdick Rev.

E.Swartz

1.8K

Transmit signal-tracing points (see text)

G

Date

1/5/02

Appendix B

Sht.

2 of 2

To ATU-P2
2

To RF-J8

4

6

8 10

J2

P3

(Note 1)1Premix Band-Pass Filters
Band 1

C2

RF Band-Pass Filters

C4Band 1

C12(See Note 2)

C1

C5
L2

2

9
3

K1B

8

4

Band 2

C7

4

PA

5

6

7

8

1

3

5

7

9

Low-Pass Filters
Band 1

C14

C11

L10

L9

C15

2

L6

L5

K2A

3

7

9

K2B
8

4

Band 2

C17

C9

K3A

C19

L3

C20
L7

L4

L8

RF IN

RF OUT

PIC16C620A

1
2
3Band 2

X1

4

6A

X2

5

K1A

6

RY COM

7

8

7
8

XOSC

C22

7

3

C23

K3B
4

Band 2
L12

U1

C27
.047

/AGC OFF

Band 1C21

I/O Controller

C16

C10

2

L11

C18

C8
C6

9

3

C13

C3

L1

2

9

PREMIXATTN RY

RA2

RA1

Z1
4 MHz

C24

C25

C26

18
17

RA3

RA0

RA4

OSC1

MCLR

OSC2

VSS

VDD

RB0

RB7

RB1

RB6

RB2

RB5

RB3

RB4

10

1

K1

10

1

K2

16
15
14

R1

13

100

12
11
10

/AGC OFF

2

3

4

5

6

7

8

1

2

3

4

5

6

7

8

P2

P1

C29
.001

1

C30
.001

To RF-J6

To RF-J7

10

K3

To ATU-P1
6R/AUX

1

J1
1

2

3

(Note 1)

Notes:
1. J1 and J2 are supplied with the KAT1 option (Antenna Tuner).
If the KAT1 is not installed, J2 pins 2 and 10 must beconnected using a jumper (see text).
2. See Parts List for values of all band-specific components.
3. K1-K3 are latching relays, and are shown in the RESET position.
Pins 5 and 6 of relays are not connected internally, but may be
used as tie points for other circuitry on the PC board.

Elecraft K1 2-Band Filter Board

4. This schematic is for the 2-band Filter board. Refer to KFL1-4
manual for 4-band Filter baord schematic.

Appendix B

B y W. Burdick Rev.

E.Swartz

E

Date

Sht.

1/5/02

1 of 1T-R

BUFFER

XMIT
MIXER

*

T-R

BANDPASSFILTERS

T-R

DRIVER

POWER
AMP
(5W)

*

LOWPASSFILTERS4.915 MHzAGC

RCV
ATTEN.

XMIT
ATTEN.

RCVMIXER

CRYSTALFILTERPROD.
DETECTOR

A.F.
PREAMP

4.915 MHz11.915 - 12.065 MHz (40 m)
AF AMP*
VFO
3.085 - 2.935

15.000 MHz(40 m)PREMIX

KEY
Common

BFO
4.915 MHzBANDPASSFILTERS

Transmit

Receive**

On Filter
PC BoardMCU

DISPLAY
AND
CONTROLS

Appendix C

K1 BLOCK DIAGRAM

W. Burdick/E. Swartz

Rev. A 8-16-00

Appendix D. K1 Assembly Photographs

Completed K1 with
top cover and side panels
removed; Front Panel and2-band Filter board shown
Plugged into the RF board.

RF board withbottom coverAttached(headphone jack isvisible at left)

Front Panelassembly

2-Band Filter Board

Appendix E, Troubleshooting

General Troubleshooting (00-19)
Problem
00 Unit appears to becompletely dead whenpower switch is turnedon (no display, no
audio); possible
smoke, hotcomponents, etc.

General Troubleshooting Procedure

Look for your problem in the Troubleshooting Tables.
Closely examine PC boards for poor solder joints and incorrect, broken or
missing components.
Follow the step-by-step receiver and transmitter Signal Tracing
procedures at the end of this section.
Check voltages using the DC Voltage Table at the end of this section.






Error Messages

00-19
20-39
40-59
60-79
80-99

01 LCD or LED
problem
02 B A T L O
displayed
03 No audio
04 Switches or
potentiometers do not
function correctly or
are intermittent
05 Current drain isexcessive on receive
06 Supply voltage
drops when K1 is on
07 Error in actual vs.
displayed frequency
08 Freq. drift or
instability
09 EEPROM init
is pending
10 EEPROM wasjust initialized

Note: Components are identified by their PC board and reference designator.
For example, "FP-U1" means U1 on the Front Panel board.

15 E N D or P = 0 is
displayed on keydown

If you see a message such as E 3 0 on the LCD, look up the corresponding
entry in the Troubleshooting Tables. Error messages can usually be cleared bypressing any switch. However, the cause of the message should be investigatedbefore continuing to operate the transceiver.

Troubleshooting Tables
There are five troubleshooting tables (listed below). Within each table,
problems are identified by 2-digit numbers for cross-referencing purposes. In
most cases you’ll know which table to look in based on the symptoms you
observe. If in doubt, start with the General Troubleshooting table. Some
problem identifiers have corresponding error messages (see above).
General Troubleshooting
Display and Control Circuits
VFO and Premixer
ReceiverTransmitter and Keyer



1





Troubleshooting Steps
Make sure your power supply is connected,
turned on, and not plugged in backwards
Check fuses; examine cables for open/short
Check resistance to ground on 12V, 8V, and6V lines; check for RF-Q7 tab short
Verify front panel and filter boards areplugged in, with connectors fully seatedMeasure the +6V and +8V regulated power
supplies (20)Check the MCU, FP-U1 (26)
See control circuits (24)Battery voltage may be below 9 V. Recharge
the battery as soon as possible.
See Receiver troubleshooting table (60)
Front panel board may not be plugged in
Check the MCU (26)Check all regulated supply voltages (20)Check switches and related components (21)Check regulated voltages (20); look for acomponent that’s warm to the touch
Check receive-mode current drain (05)Battery not fully charged
See Operation section (VFO Calibration)

See VFO troubleshooting table (40)

See Advanced Operating Features,
Resetting to Factory Defaults (page 57)
You may see E 1 0 one time on power-up, or
if you install a new version of the firmware.
All K1 parameters are set to defaults.
E N D : TX out of range (see specifications)P = 0 : TX disabled via O U T menu entry












27 Filter board notplugged in, or I/O
controller (FIL-U1)
communication
problem

Display and Control Circuits (20-39)
Problem
20 Regulated
voltage(s) incorrect

21 General problem
with switches or
potentiometers
22 +6A or +6B
voltages too low(< 5.7V)













23 +8V too low(< 7.5V)
24 LCD or LED
problem

25 Relay Problem

26 Possible MCU
problem













Troubleshooting Steps
DC input voltage must be > 8.5V
Remove all option boards and re-checkIf +6V is too low (< 5.7V) go to 22
If +8V is too low (< 7.5V) go to 23
Check switch resistance open/closed; check
R14, R15 and RP1
Check resistance of potentiometers; check
related connections to FP-J1
Remove socketed ICs, front panel board,filter board, and options individually
Inspect the entire 6A or 6B path on the RF
and Front Panel boards.
Check for regulator ICs installed backwards
Lift the output lead of the affected regulator
and measure the voltage this lead; if thevoltage is still too low, replace the IC
Lift other component leads on the 6V line asneeded to find cause of excess loading
Use techniques given for 6V regulators(above)
LCD in backwards or bent pin; check for
shorts to ground on each LCD pin
MCU pin bent or broken (FP-U1)
LEDs swapped or installed backwards
Relays installed backwards or not soldered
Check relay coil resistance, pins 1 and 10
I/O controller defective or backwards (27)Check all DC voltages on FP-U1
Remove the Front Panel board and inspect
U1. Make sure it is not backwards, has nobent pins, and is seated firmly in its socket.
Check oscillator components (X1, C1, C2).
Also see (33) if you suspect an error in amenu parameter, etc.







28 I/O controller data
error



29 AuxBus problem







30 EEPROM
write/read test #1
failed31 EEPROM
write/read test #2
failed32 EEPROM dataerror
33 Configuration dataor menu problem

2









If you saw the message E 2 7 , the I/O
controller (IOC, FIL-U1) did not respond tomessages from the main processor (MCU,
FP-U1). Turn power OFF and back ON; if
you hear some relays switching, the IOC may
be OK, and the problem is likely to be with
the AuxBus (29)
If you do not hear any relays switching on
power-up, your IOC (FIL-U1) may be
defective. Inspect FIL-U1 to see if you haveinstalled it backwards or if any pins are bent.
With power ON, check all voltages
associated with U1. You should see 6V atpins 1 and 14. See DC voltage table.
If you saw the message E 2 8 , the I/O
controller (IOC, FIL-U1) sent an incorrect
response to the MCU (FP-U1). This may
indicate a firmware incompatibility.
Try removing each option board
If voltage at pin 13 of the IOC (FIL–U1), theauxBus line may be shorted
Try tapping the B A N D switch quickly while
watching pin 13. It should drop below 6V
briefly if the MCU (FP-U1) is sending amessage to the IOC.
Check the AuxBus signal at the MCU, pin 8(FP-U1). The voltage should drop below 6V
briefly when the band is changed.
If you E 3 0 , E 3 1 or E 3 2 on the LCD, oneof the EEPROM tests has failed. CW
memories cannot be used. Parameters will be
set to defaults, and band 1 will be selected.
Verify that the Filter board is plugged in.
Check all voltages on the EEPROM (FP-U3)
Inspect FP-U3 and surrounding traces
Make sure FP-R16 is installed
If a menu parameter is out of range or can’t
be modified, EEPROM may need to bereinitialized. See page 57 for instructions.

VFO and Premixer (40-59)

Receiver (60-79)

Problem
40 General VFO
problem; frequency
jumps or drifts

Problem
60 Low (or no) audio
output from receiver,or general receivergain problem








41 Can't tune VFO (orRIT/XIT offset)







42 VFO inductor not
installed or VFO notoscillating







45 VFO tunes thewrong way
46 VFO or RIT/XIT
range is too large, too
small, or shifted
low/high







Troubleshooting Steps
Note: Some VFO drift will always be present
due to aging of components and heating or
cooling of the cabinet
The VFO will drift more if you used thelarger range (C2=120 pF).
Use C A L menu entry to check actual VFO
frequency (hold E D I T to show the operating
frequency calibration display, then switch toO S C using D I S P L A Y )Make sure supply voltage is above 8.5V
If you used solder with water-soluble flux,
clean the board with hot water and a Q-tip
Make sure L1 leads are properly stripped
Check crystals on Filter board
Check actual VFO range (40)
Measure voltage on anode of RF-D3 (VFO
main varactor diode) while tuning VFO pot
Measure voltage on anode of RF-D4 (offset
varactor diode) while tuning the OFFSET pot
Varactors may be installed backwards
If you see E 4 2 , the VFO signal is either
missing or is too low in amplitude to be
counted by the MCU (FP-U1).
Check all VFO components
Check the counter amplifier and related
components (FP-Q1, R11, R12)
Use signal tracing to determine where the
VFO signal is getting lost
VFO pot (FP-R1) CCW and CW leads may
be reversed
Check actual VFO range (40)
Varactor diodes may be wrong type
Check all capacitors in VFO, esp. C2 and C7
See Alignment and Test, Part I.











62 Signal loss only on
one band

65 AF amplifier notworking

70 AGC or S-meternot working

3






Troubleshooting Steps
If you hear normal audio output on one band
but not all bands, see 62
Make sure you have headphones or speakerconnected; turn AF GAIN clockwise
Check the key jack for a short to ground
Make sure the attenuator is turned off
Re-peak the band-pass filters
Check for ground shorts in the LPF and BPF
Turn the AF GAIN to maximum. If you don’t
hear any “hiss” at the receiver output,
troubleshoot the AF amplifier (65)
Check the 8V regulated supply voltage andtroubleshoot if necessary (20)
Try using signal tracing (see procedure laterin this section)
Re-do alignment on affected band
Check the band-pass and low-pass filters andcrystal for this band
Check functioning of the associated relays(change bands, then measure relay leads thatshould be open or shorted for that band)
Use the S T L menu entry to set a sidetone
level of 31. If you hear a strong tone, the A.F.
amplifier (RF-U4) is probably working, andthe problem is likely to be with the preamp(RF-U3) or other RF board circuits.
Signal trace through the receive chain
backwards by touching a tool or wire tovarious points along the receive path
Check all DC voltages in the receiver
Inspect the A.F. amp and preamp circuits
Make sure the attenuator is off
Check voltages on RF-U1, U2, Q1, Q2, D2

88 Power output
fluctuates

Transmitter and Keyer (80-99)
Problem
80 General
Transmitter problem







86 Power output is
low or zero
















Troubleshooting Steps
If power output is too low, go to 86
If power output slowly increases during keydown, go to 88
If current drain on transmit is too high for the
given power level, go to 92
If the transmitter output power seems to beunstable go to 88
If the transmitter stops transmitting by itself
go to 90
If the keyer isn’t working properly, go to 95
Try signal tracing
Check power output when using a 50Ω
dummy load; if the output is correct on adummy load but not when using an antenna,
your antenna is probably not matched
Check all component values in the RF
detector; you may have two resistors
swapped (R36, R37) or the wrong detector
diode (D15, should be 1N5711)
You may have a short in the LPF or BPF;
also check relays (25)
Examine T3 and T4; these must be wound as
indicated in part II of the RF board assembly
Look for toroid leads that are not completely
stripped or are soldered poorly
Check all DC voltages in the transmitter (RFboard, Q5/Q6/Q7, U8, U9)
If drive is lacking, R35 (RF board, TX
attenuator) can be made larger, at the expenseof power-setting resolution.
Make an RF probe and signal-trace throughthe transmitter to find where signal is lost(see probe and procedure later in this section)
Check for any components getting hot
Check for RF-Q7's tab shorted to the rightside panel (ground)








90 Output power
drops to zero suddenly

92 Current drain toohigh on transmit



95 Keyer Problem






4

If you stay in key-down (TUNE) mode forseveral seconds, it is normal to see someincrease in power; this is due heating of the
final amplifier transistor.
If power goes up and down significantly
during normal keying, you may have apoorly-matched antenna OR you may havepower set too high for your battery or power
supply to handle; try reducing power
Make sure none of the diodes in the T-R
switch circuits are in backwards
If the transmitter is unstable (oscillating)even when connected to a 50-Ω load, you
may have an incorrect component value or a
toroid-winding error (86)
If you have transmit power set too high foryour battery or power supply, the supply
voltage may drop so low on transmit that it
resets the MCU (FP-U1) or the I/O controller(FIL-U1). Reduce power.
You may have power set higher than the final
amplifier can achieve for a given load or
power supply voltage, resulting in overdriveof transmitter stages. Reduce power to see if
normal current drain is restored.
Damaged PA transistors or other components
could cause inefficiency in any stage of thetransmitter. Check all DC voltages andcomponents; signal trace if necessarily (86)
If the keyer is generally erratic whentransmitting and seems to get worse as power
is increased, you probably have RF leaking
into the keyline. Try bypassing your key with.001 µF capacitors; also try 100 µH RF
chokes in series with the paddle connections.
Seek a better antenna match
Improve your ground system (if you have RF
problems, add two or more radials cut to 1/4wavelength at the affected frequency)

Signal Tracing+

You can solve nearly all problems yourself by signal tracing using an RF probe
and signal source, such as the ones shown here.

.01µF

8-14VDC
22K

RF Probe

X1 (see text)

2N2222A,
2N3904, etc.

The RF probe shown in Figure 1 converts RF signals to DC so they can bemeasured using a DMM.

RFOUTPUT
Level

E1
probe
tip

C1
.01µF

E2

R1
4.7Mohm

560Ω

COAX,
12-36" (30-90 cm)

J1

39pF
10K
150pF

1

50 or 100Ω
(non-inductive)

2

D1
1N34A

To DMM

Figure 2

groundFigure 1

Receiver and VFO Signal Tracing
In the following steps you’ll use an RF probe, DMM, and a signal source tofind the stage where the received signal is getting lost or attenuated. You canthen use voltage tables and resistance checks to find the bad component orconnection. Space is provided at each step to record your measurements, which
can vary as much as 25% in most cases and still be acceptable. Test points andcomponents are on the RF board unless otherwise indicated.

The probe tip (E1) should be no longer than 3” (see any ARRL Handbook forideas), and you should not touch the tip while taking measurements. Use analligator clip at E2, with a 4” (13 cm) lead.
Note: With this RF probe, DC voltage readings on your DMM will beapproximately equal to the signal voltage in Vrms (root-mean-square).
However, the error in the reading is quite significant for small signals (typ.
–50% at 50 mVrms). The signal tracing procedures take this error into account.

1.

Crystal Oscillator

2.

The simple crystal oscillator shown in Figure 2 can be used in lieu of acommercial signal generator. It will run on voltages as low as 8 V, but 12 V or
higher is recommended.

3.
4.

The components are not critical, and can vary 20% with little variation in
performance. Nearly any NPN RF transistor will work in the circuit. Crystal X1
should be chosen for the band in use. The potentiometer can be any small
trimmer or panel mount unit, but should not wire-wound.

5.
6.

5

Connect the RF probe’s output to your DMM’s +/- DC input jacks. Select a2 or 3-V DC range.
The DMM should read close to 0.000 V DC, and the reading should
increase when you touch the RF probe tip with your finger.
Turn on the K1 and switch to the desired band. Use the menu to turn AGC
OFF. Set AF GAIN to minimum.
Connect the RF probe’s ground clip to the ground jumper near the VFO
inductor, L1. The probe tip will be touched to the points indicated in thefollowing steps.
VFO: U7, pin 1 (U7 is near the left edge of the RF board). Expected DMM
indication: .02-.04 V (DC). Actual: _______.
Premix crystal: U7, pin 7. Expected: .04-.25 V. Actual: _______.

7.

Premixer: U7, pin 4 or 5 (whichever is greater). Expected: .04-.25 V.
Actual: _______.
8. Premix band-pass filter: FIL-P1, pin 6. (FIL-P1 is an 8-pin connector on
the Filter board, near the crystals. Pin 6 is the third pin from the right end.)
Expected: .04-.15 V. Actual: _______. (Note: the expected voltage takes
into account the de-tuning effect of the RF probe. The signal level would
be higher if the filter was re-tuned to compensate for it.)
9. BFO: U2, pin 7. Expected: .015-.100 V. Actual: _______.
10. Connect a signal generator or test oscillator to the antenna jack. Set thesignal level to about 0.14 Vrms as indicated by the RF probe, with theprobe tip on pin 8 of FIL-P3 (right-hand end of the 8-pin connector on theFilter board near the antenna jack).
11. Low-pass filter: FIL-P3, pin 1. Expected: .12-.16 V. Actual: ______.
12. T-R switch: FIL-P2, pin 8 (P2 is the front-center 8-pin connector on theFilter board). Expected: .07-.12 V. Actual: _______.
13. RF band-pass filter: FIL-P2, pin 1. Expected: .06-.13 V. Actual: _____.
14. Attenuator and T1: U1, pin 1. Expected: .40-.70 V. Actual: ______.
15. Receive mixer: U1, pin 4. Expected: .50-.80 V. Actual: _______.
16. Post-mixer amp: R14, right end. Expected: .50-.80 V. Actual: ______.
17. Connect a pair of headphones or a speaker and adjust the AF GAIN so thatyou can just hear some background noise. Tune the VFO until you can hear
the signal from your test generator peaked in the crystal filter. Since AGC
is turned off, the signal may be extremely loud and will probably beclipping (distorted) at the AF output.
18. Crystal filter: U2, pin 1. Expected: .30-.50 V. Actual: _______. (Re-peakthe signal using the VFO as needed.)
19. Disconnect the RF probe from the DMM.
20. Set up the DMM to read AC volts, 20 or 30-V meter range. Connect the () lead of the DMM to one of the ground test points using an alligator clip.
The (+) lead will be touched to the points indicated in the following steps.
21. Product detector (saturated output): U2, pin 4. Expected: .40-.80 V (ACrms). Actual: _______. (Re-peak the signal using the VFO as needed.)
22. AF preamp: U3, pin 5. Expected: 2-4 V. Actual: _______.
23. AF amp: U4, pin 6. Output voltage should vary from 0 to about 4 or 5 V
as the AF GAIN control is varied.

Transmitter Signal Tracing
In the following steps an RF probe is used to determine where the transmitted
signal is getting lost or attenuated. These checks are made from the bottom sideof the RF board so that the Filter board can be left plugged in. Each transmit
test point is clearly labeled, with a small arrow pointing to the appropriate PC
board pad. You’ll want to refer to the transmitter schematic (K1 RF Board,
sheet 2) as you perform the measurements.
1.
2.
3.
4.
5.
6.

Do the VFO and receiver signal tracing first to check VFO/premix signals.
Connect a dummy load to the antenna jack.
Turn the K1 upside-down and remove the bottom cover.
Install a very short jumper from the point labeled DRV to ground. This
allows measurement of all low-level transmit stages.
Turn on the K1 and switch to the desired band. Set the power level to 3
watts using the OUT menu entry.
Connect the RF probe’s ground clip to the ground jumper on the bottom of
the RF board, near the center. Connect the RF probe’s output to the DMM,
and set the DMM for DC volts (2 or 3 V scale).

In the remaining steps, touch the RF probe tip to the indicated points and enter
TUNE mode to take a reading. (Hold WPM+/WPM- together to activate
TUNE.) Cancel TUNE after each reading by tapping any other switch.
Note: Do not key the transmitter for more than about 10 seconds at a time.
7. PRE (premix): Expected: .04-.09 V (DC). Actual: _______.
8. ATTN (TX attenuator): Expected: .02-.05 V. Actual: _______.
9. OSC (TX 4.915 MHz): Expected: .01-.04 V. Actual: _______.
10. MIX (TX mixer): Expected: 0.1-0.2 V. Actual: _______.
11. BUF (TX buffer): Expected: 1.5-2.0 V. Actual: _______.
12. TR1 (first TX T-R): Expected: 0.5-1.0 V. Actual: _______.
13. BPF (band-pass filter): Expected: 0.5-1.0 V. Actual: _______.
14. TR2 (second TX T-R): Expected: 0.5-1.0 V. Actual: _______.
15. TR3 (receive signal shunt): Expected: < .01 V. Actual: _______.
16. Remove the short from DRV to ground. Set DMM scale to 20 or 30 V.
17. DRV (driver): Expected: 0.9-1.6 V. Actual: _______.
18. PA (power amp): Expected: 10-15 V. Actual: _______.
19. ANT (low-pass filter): Expected: 10-12 V. Actual: _______.
20. Disconnect the RF probe. (The last measurement is DC volts, not RF.)21. RFD (RF output detector): Expected: 1.7-2.0 V. Actual: _______.

6

DC Voltage TableNOTES: Measurements listed for FIL-U1 apply only to the two-band Filter board; for 4-band Filter board voltages, refer to the KFL1-4
manual. Measurements were made with a 50-ohm dummy load connected and a supply voltage of 14 V. In general, your measurements should
be within 10% of the values shown. Pins NOT listed in the table should indicate 0.0 volts DC. Pins marked with (*) are hard to measure
due to noise pickup. Shaded areas show transmit-mode measurements (using TUNE), made with the Filter board removed.
Reference designators are prefixed with the board identifier: “FP” = front panel board, “RF” = RF board, “FIL” = filter board.

Ref.
FP-U1

Pin
1
2
3
4
5
6
8
9
10
11
13
14
15-17
18
19-22
23
24-30
32
33-39
40

VDC
6.0
1.1
6.0
1.8
6.0
2.5
5.6
3.0
3.0
6.0
2.3
2.8
3.0
6.0
3.0
6.0
3.0
6.0
3.0
6.0

Ref.
FP-U2

Pin
1
3
4
7

VDC
1 to 5
6.0
6.0
6.0

FP-U3

5
6
8

6.0
6.0
6.0

FP-U5

1, 2, 3
5
6
7
8

3.0
6.0
4.8
4.8
6.0

Ref.
FIL-U1(2-bandboard)

Pin
3
4
13
14
15
16

VDC
0.8-1.0
6.0
5.5
6.0
< 0.3
< 0.3

Ref.
RF-U1

RF-U2

RF-U3

7

Pin
1
2
4
5
6
7
8

VDC
1.4
1.4
4.9
4.9
6.0
5.3
6.0

1
2
4
5
6
7
8

*
1.4
*
*
6.0
5.4
6.0

1
2
3
5
6
7
8

1.3
*
*
4.0
8.0
4.0
1.3

Ref.
RF-U4

Pin
6
7
8

VDC
6.6
13.6
6.8

RF-U7

1
2
4
5
6
7
8

1.4
1.4
4.8
4.8
6.0
5.3
6.0

RF-U8

1
2
4
5
6
7
8

Ref.
RF-U9

Pin
2
3
6
7

VDC
6.8
6.8
6/8
13.6

RF-Q6

B
C
E

1.1
13.6
0.5

RF-Q7

B
C
E

0.0
13.6
0.0

APPENDIX F. PARTS PLACEMENT DRAWINGS (including 2-band Filter board)
J3
C13

RFC2

AUX

U5

C45
D13

U9

U8
R11

C58

R35
RP5

1
U7

D10

Q5

C60

J6

C75

C40

+
C33

1

C9

Q2

C69

D4
R13
C6
C72 C18 R21
U3

C74

C73

1

3 R14

2

4

T1

+

RP1 X1
1+
C68 Q11
C54

J10

1
RFC9

J9

C5

X2

U2

R5

R6

D7
2

R3

T2

1

3

K1 RF Rev. E
2001 ELECRAFT

C10

1

R4

D8

C61

C17

PRE
TR2

C37
R1

C20

S2

DRV

J1

D6

ATTN

MIX

TR1

Q3

C22

OFS
OPER TEST(NOT GND)

1
C21

Q1

X5

R2
RFC1

Q10

BPF

C1

OSC

BUF
TR3

Q7

4

4

C64

RP3

J2

C71
C70

12V
PA C78

3

T3

R39

R27

3

2

C19 C66

R17

D1
D2

RFD

4

U1

D17

D3
Q8

U6

+
C7
C4

D15
R34

1

K1

D5

R36

T4

2

J7

J8

RFC5
C55

R30 R33

Q6

1

ANT

C52

1

C44

C59
C14

C43

R25

C50

R26

C2

U4 Q9

S1

RFC3

L1

R7

C48

D9
+

R20

D11

D12

R37

1 P3

Q4 1

R24

RFC4

C15
D18
R19
1

J4

C47

1252

602

K1 KAT1

C49

+

C76

Q14

C3
C62

RF DET

L2 J5

12V

X6

X4

C38

C36

RFC6

X3

SPKR

P1

20

10

1

P2

C34

C8

CUT=MONO

D1

S1

D2

K1 FP

S4

2001 ELECRAFT

Rev. E

U3

358
RP1

R8

C4

R7

U5

R9
S2
S5

S3

R3

R2

R1

U4

R19

L6

L1
C1

L2

C3

C4 C12

L5

C6
X2

C8

L4

C25

C26

20

P3

R16

X1

R12
1

1

C22
L7

C18

L8

Z1

C23
C21

K3

K2

K1

2000

U1
X1 C29

R14
R15

C2

C1
RFC2

J1

U2

U1

RFC1

C13

C2
L3
C7

K1 FIL 2 Rev. D
C24
ELECRAFT

C6

Q1
R6

S6

R13
1

1

C5

(SOCKET)

R1

L9
J1

L10
P2

1

P1

1

ELECRAFT K1 QUICK REFERENCE
Tap once to show band,
tap twice to change bands

LEDs

LCD

Hold to select display
mode: normal, S-meter,or BAT (supply voltage)

RX: VFO freq or S-meter
TX: bargraph, 1 bar per watt

BAND

RIT / XIT - GREEN / ORANGE
ATTN - YELLOW

RIT / XITELECRAFTDISPLAY
MENU

ATTN

WPM +
1

TX

XFIL

RX

WPM -

K 1 TR ANS C EIVEREDIT

Tap for WPM up,
Hold for FL1/2/3

T
2

Tap for WPM down,
Hold for ATTN on/off

ATTN

AF GAIN

MSG

RIT

-

+
REC

XIT [PFn]

Tap for RIT on/off, hold for XIT on/off(PFn normally = XIT; see MENU)

MENU

Hold both for TUNE;
during TUNE, canchange power w/WPM+/-

Tap to play message 1 or 2,
hold to record message 1 or 2
(when prompted with "1-2"during message play,
tap 1 or 2 for single play,
hold 1 or 2 for auto-repeat)

VFO

Tap to enter menu, hold to edit; use WPM+/- to scroll menu or modify parameters

OUTT
T

POWER OUTPUT, 0.1-7.0 W(hold DISPLAY to select P=0)

STLT

SIDETONE VOLUME LEVEL, 0-31

STP T

SIDETONE PITCH (Hz) or SPOT

T-RT

QSK DELAY, 0 - 900 ms

RPTT

AUTOREPEAT DELAY, 0-255 sec

INPTT

KEYING DEVICE: Hnd, PDn, PDr

IABT

IAMBIC MODE, A or B

AGCT

On or Off

LEDT

RIT/XIT/ATTN LEDs On or Off

FLxT
T
T
BxT
T
T

CALT
T

Operating freq. cal (OPF), per-band;
hold DISPLAY for VFO display (OSC)

SIG T
T

S-METER ZERO SET: Lxx, xx = 30-70(hold DISPLAY for scale: H x, x = 2-6)

XTAL FILTER BW, 200-900 Hz(hold XFIL to select FL1/2/3,
then tap WPM +/- to set bandwidth)

NBT

NOISE BLANKER: Off, HIGH, LO

ATUT

AUTO-TUNER mode (see ATU manual)

BAND ASSIGNMENT, MHz(tap BAND to select B1 or B2; 30m:
hold DISPLAY to select 10.0/10.1)

PFnT
T
T

PROGRAMMABLE FUNCTION;
shortcut to selected menu entry, or
set to "NOR" (normal) to use as XIT