HDTenEightyP/NetNews huggingface dataset:
Organization: Queen's University at Kingston
Date: Thursday, 16 Apr 1992 19:10:28 EDT
From: <LEEK@QUCDN.QueensU.CA>
Newsgroups: sci.electronics
Subject: Re: Panasonic Printer Memory (repost +ASCII pictures)

In article <1992Apr14.211802.21682@den.mmc.com>, pschauer@den.mmc.com (Paul
Schauer) says:
>
>Forgive me if this is the second time this req shows up. My posting
>program sent my last one off to lala land (I think...).

Okay.  Someone else also email me.  I think it is time for a repost +
some additional ASCII picture in case some of you have doubts.

Well you get yourself a 32K static Ram chip (120ns or faster).  Pop open
the printer.  Pop the front panel off in case you have problem finding
the screws.  Those guys hide them in the front.  There are 3 philips
screws in the front behind the panel.  You'll need to remove the paper
knob too.

                                       See seams here
       Back                               V  Jam a plastic ruler
    _________----------------------------- _   along the seams
   | ||||||                               | |    and pop the panel
   |                                      | |   ---->  off the front
   >______________________________________|__\
    \                                         |
   ^ \________________________________________|
   |
   |
 Hinge                                    ^  lift top gently
               ----------------------------
                                           |   3 screws hidden behind
                                           | V the front panel
                ___________________________|__
                                              |
                 _____________________________|

Remove screws & paper knob.  Lift top up from the front.  There are
plastic taps thing at the back to hold it down.  Just lift the top
to about 45 degrees and the whole top should come off.    (gently!!)


There is only 1 empty 28 pin socket on the whole PC board.  There is
even a indicator for the pin 1 (if not,line it the same way as the 128K
ROM chip next to it.  Most good designs have chips facing the same way.
They'll have a fun time to reroute all the lines between the ram & rom
just to confuse you.  :)  <- If you know which one is the rom, you'll not
going to have problem :)  Assemble & test.  (If you don't trust yourself,
reverse the order of the two.)  Try printing a high-res graphics file
and set the printer to do a didirectional mode to test out the buffer.
Enjoy !!  I did.

K. C. Lee
Elec. Eng. Grad Student
P.S. May be someone can answer this next time.... :)
From: dmackie@sdcc13.ucsd.edu (Dave Mackie)
Newsgroups: sci.electronics
Subject: Source for National LM-2002
Date: 16 Apr 92 17:09:32 GMT
Organization: University of Confusion, San Diego

As the subject says: I need a source for LM-2002's (either  T or AT)
These are 8 watt audio amplifiers, 5 pin TO-220 configuration.

Mail order is fine.
Quantity small (less than 10).

Feel free to post responses as I read this newsgroup all the time :)

-dave
From: dcd@qed.cts.com (Scott Hanson)
Newsgroups: sci.electronics
Subject: 1/4" connector question
Date: 13 Apr 92 22:04:01 GMT
Organization: The QED BBS, Lakewood CA

I recently acquired a quantity of 1/4" plugs.  They are all metal, and
impossible to open nondestructively.  Close inspection reveals a tiny
pin inside (where the signal would be) and a strange cutting screw
(which would cut through the insulation and contact the shield).
I have had little luck getting these to work.  They seem to be solderless
connectors designed to be quick and easy (and unreliable)  I would like
any suggestions on how these were designed to work.
Thank you in advance.

------------------------------
dcd@qed.cts.com (Scott Hanson)  or  qed!dcd
The QED BBS -- (310)420-9327
Newsgroups: sci.electronics
From: chaplin@keinstr.uucp (Roger Chaplin)
Subject: Re: MC68000
Organization: Keithley Instruments, Cleveland, Ohio
Date: Thu, 9 Apr 1992 17:35:14 GMT

In article <1992Apr7.183518.1356@ucsu.Colorado.EDU> rainer@spot.Colorado.EDU (Rainer Malzbender) writes:

>Basically what you need is a signal that says "I'm booting". If you're
>building a system with a UART, a good choice is the 2681. In addition
>to two uarts, it also has several I/O pins which can be used for any
>purpose whatever. I used one of these as my "boot" flag - it gets set to
>some state (I forget which - high, I think) on power up, and my software
>resets it to the other state after we're on the air.
>
>This boot signal goes into the address decode PAL, which generates device
>selects based on the address and a few other signals. The PAL maps ROM
>into low memory if the boot flag is on, high memory otherwise.

However, this may complicate things if you intend to use the 68k's
RESET instruction.  This momentarily turn's the chip's RESET/ pin into
an output and pulls it TRUE, resetting any peripherals connected to
it.  However, the RESET instruction does not reset the 68k.  This means
that your program must clear the "boot" flag after a RESET instruction
before it attempts to access RAM.

This all assumes that you have designed your hardware properly: it is
tempting to tie HALT/ and RESET/ together to the output of whatever
generates the power-on reset signal.  If you do this, the RESET
instruction will pull HALT/ TRUE, causing a reset of the 68k in
addition to all of the peripherals.

-- 
Roger Chaplin / Instruments Division Engineering
chaplin@keinstr.uucp / CI$: 76307,3506
nuthin fancy here . . .
From: cyberman@toz.buffalo.ny.us (Cyberman)
Newsgroups: sci.electronics
Subject: what are these chips?
Date: 11 Apr 92 02:31:21 GMT
X-Maildoor: WaflineMail 1.00r

JP>MAX232cpe

RS232 level convertor that can be rn on a single 5v supply.  It
generates it's own +-12v power.

        STEPHEN CYBERMAN@TOZ.BUFFALO.NY.US
        commiserated at Fri  04-10-1992  17:52:29
---
 * SLMR 2.1a * Remember pillage before you BURN!(Congress proposes a TAX
From: mcovingt@athena.cs.uga.edu (Michael A. Covington)
Newsgroups: sci.electronics
Subject: Re: Repetitive clicks when playing tapes
Date: 7 Apr 92 20:27:44 GMT
Organization: University of Georgia, Athens

Do the clicks correlate with the rotation of one or the other of the
little reels in the cassette?

Do you get them when playing all tapes or only some?

I've had clicks of this kind result from a tape being exposed to a
magnet of some sort.

-- 
==========================================================================
Michael A. Covington, Ph.D. |  mcovingt@uga.cc.uga.edu  |  ham radio N4TMI
Artificial Intelligence Programs | U of Georgia | Athens, GA 30602  U.S.A.
==========================================================================
From: philip@cetia.fr (Philip Peake)
Newsgroups: sci.electronics
Subject: Re: Jacob's Ladder
Date: 15 Apr 92 15:38:06 GMT
Organization: CETIA, France

In article <kyZyiB1w164w@inqmind.bison.mb.ca> magus@inqmind.bison.mb.ca (James Copland) writes:
>Yes!  But its not "truly" a Tesla coil until you include the "rotary 
>spark gap" in the primary circuit.  I have used B/W tv high voltage 
>sections and gotten 7 - 18 KV and color ones ranged for me from 20 - 
>48Kv.  Nominal is B/W 15KV and color 40KV so you can see most of them are 
>lower than the nominal.  They make great Jacobs ladders and other Tesla 
>type toys.  I like the "Plasma Ball" the best, as you can safely interact 
>with the lightning.  Now if I could only use some electronics to build 
>the equivalent "solid state"  spark gap!

Lots of TV circuits make use of tripler circuits to boost the EHT.
This makes the EHT transformer cheaper, the insulation doesn't have to
be as good, and it uses less copper wire.

As to "Plasma Balls", do you know how to build one ?
I always assumed it has a strange mixtures of gasses at low pressure ...
If it is possible to build such a toy, I'm interested ...

Philip
From: adams@pdv2.fmr.maschinenbau.th-darmstadt.de (Adams)
Newsgroups: sci.electronics
Subject: Re: Hex-FET's and infinite impedance
Date: 9 Apr 92 18:27:50 GMT
Organization: TH-Darmstadt

In article <4764@umriscc.isc.umr.edu> dshipley@cs.umr.edu (Dan Shipley) writes:

>   I just got a car audio amplifier from Coustic.  In the manual, it says it  
>   uses hex-FET's and NOT to turn the amplifier on if there is no load on the  
>   outputs.

>   I don't know anything about hex-FET's, but it seems unusual that an infinite  
>   output impedance would cause damage to a transistor.  However, I'm always  
>   learning just how much I don't know, so if someone could enlighten me in the  
>   ways of hex-FET's or why this might cause damage, I'd be grateful.

first guess (using hexfets as a linear voltage controlled current source):
How about oscillating? It is not so uncommon, that amplifiers may not 
be operated without specified burden. It is not uncommon, that 
infinite impedance (e.q. no burden) fries an output stage. Ask an RF engineer..

second guess (hexfets used as current switches): As you can use it as a
voltage controlled current source, and switch it very easily, you can use
it as driver stage in a a low resolution (down to 1bit) D/A converter.
To obtain your signal, you need a reconstruction filter. This may be 
the impedance of your speaker set / earphone. As much as I know, some
walkmans by Sony use this strategy.

Just guesses... adams.

If I am wrong, please tell me so --- but no flames.
Newsgroups: sci.electronics
From: pollock@milton.u.washington.edu (Joe Pollock)
Subject: Re: HV shocks (was: Jacob's ladder)
Organization: The Evergreen State College
Date: Mon, 13 Apr 1992 06:31:37 GMT

In article <1992Apr12.140143.420@cmkrnl.com> jeh@cmkrnl.com writes:
>
>I agree with Mike.  In fact I think you can get a deadly shock from such a
>transformer even if you are standing on the semi-mythical dry wood on glass
>insulators (do you know anyone who actually works that way?), and even if you
>touch the "hot" terminal with only one hand.  It's true that under these
>conditions the current has "no place to go", ie no ground path, but there will
>still be a very brief current flow as your body "charges up" to the potential
>of the hot terminal. 
>
>I have no idea if this amount of current, for this brief time, would be lethal
>or not, but I'm not gonna test it!  This isn't a test you get to go back and do
>over again! 
>
>Bear in mind that the shock itself doesn't have to kill you to be dangerous. 
>The shock may kill or maim by doing nothing more exotic than causing your 
>muscles to convulse, throwing you against the wall or onto the floor with 
>extreme violence.  (This is a particular hazard when working around TV sets
>without discharging the CRT 2nd anode.  The shock itself might not be lethal
>but it might cause you to swing your hand into the neck of the CRT, and if your 
>hand is holding a tool, there's a good chance of breaking it... and the 
>resulting implosion won't be pretty.)
>
>	--- Jamie Hanrahan, Kernel Mode Consulting, San Diego CA
>Internet:  jeh@cmkrnl.com, hanrahan@eisner.decus.org, or jeh@crash.cts.com
>Uucp:  ...{crash,eisner,uunet}!cmkrnl!jeh

Let's see - under the conditions of standing on a "perfect insulator," the
current limit would be determined by the capacitive reactance to ground
at 60 Hz, which should be quite high, since the capacitance will be on the
order of pf...

BTW - I found out about all of this the hard way.  I was in the eight or
ninth grade, and messing around with a sign transformer in the basement.
I had the sense to use automotive ignition wire on the secondary, and
had observed a fine corona when I brought one  wire near the insulation
of the other secondary lead.  So I had the not-so-bright idea of holding
a screwdriver in one hand, grasping the insulation of one lead, and
attempting to draw a fine corona from the other *terminal* off the 
screwdriver point.  The result was a fat yellow arc about an inch long.
My arm snapped back, and the screwdriver stuck in the wall behind me.
My arm and legs hurt for several days.  I learned to be a *lot* more
careful very quickly :-)  One of the worst shocks I ever received.

Amazing some of us ever reach legal maturity, isn't it?

--joe pollock   pollock@u.washington.edu


Organization: Music, Carnegie Mellon, Pittsburgh, PA
Newsgroups: sci.electronics
Date: Fri, 17 Apr 1992 11:41:08 -0400 
From: "Raymond C. Chick" <rc4n+@andrew.cmu.edu>
Subject: Voice Recognition

I'm looking for info on voice recognition systems for the blind. 
Especially systems that could be used with electronic music equipment,
such as MIDI sequencers. Any rerlated info would be helpfull.

Raymond Chick 
  
Xref: sparky sci.electronics:8360 rec.bicycles:9252 rec.motorcycles:12951
From: parker@gdls.UUCP (Doug Parker)
Newsgroups: sci.electronics,rec.bicycles,rec.motorcycles
Subject: Re: Sticky Demand Traffic Light problem solution
Summary: Who can post a summary of these?
Date: 10 Apr 92 18:15:56 GMT
Followup-To: sci.electronics
Organization: General Dynamics Land Systems, Sterling Heights, MI

In article <jrsargeant.702837076@node_d3ff>, jrsargeant@lescsse.jsc.nasa.gov (JACK SARGEANT) writes:
> In <1992Apr8.151153.20720@ohrd.uucp> ohrd!jlevine@cs.toronto.edu (Jody Levine) writes:
> 
> >In article <-slj0+=.jps@netcom.com> jps@netcom.com (John Serafin) writes:
> >>sagerian@delphinium.UUCP (Steve M. Sagerian) writes:
> >>

[stuff deleted]

I'm not big on electronics, so I can't tell from reading the net.responses
if there's been one or more explanation for this phenomenon.

Can someone with the understanding summarize this so we can get a better
handle on this?

Thanks,

Fly, cycle, bike, run, walk, in that order. DoD #0559
Douglas Parker      |   Computer Sciences Corporation
teemc!gdls!parker   |   Come home. (Isn't English wonderful!)   :-(
Newsgroups: sci.electronics
From: dfs@doe.carleton.ca (David F. Skoll)
Subject: Tying LSTTL inputs to Vcc?
Organization: Dept. of Electronics, Carleton University
Date: Wed, 15 Apr 1992 18:19:27 GMT

I'm using some LSTTL parts in a circuit I'm building, and some inputs
have to be tied to a constant logic "1".  Now, the technique I've
always used is to tie them to +5v through a resistor, or use a spare
inverter or NAND gate to generate a logic "1".

However, the Motorola LSTTL databook says it's OK to tie the inputs
directly to +5v.  Is this typical of all LSTTL input circuitry, or
peculiar to Motorola's?  Why in most designs I've seen do people use
either the resistor or spare gate method?  Would power-on transients
cause problems?  (That's the only thing I can think of.)

--
David F. Skoll
Organization: Penn State University
Date: Monday, 13 Apr 1992 10:15:31 EDT
From: John D. Balogh <JDB6@psuvm.psu.edu>
Newsgroups: sci.electronics
Subject: Re: Engine Knock Sensor
Distribution: na

In article <#+8tqjm@rpi.edu>, richtt@aix.rpi.edu (Timothy G. Richter) says:
>
>I need to determine the output of an engine knock sensor.  As far as I
>know, the knock sensor is a piezo-electric "microphone" which "listens"
>for knock.  Knock occurs at 6.5kHz, and the knock sensor is (I'm guessing)
>a narrow-band pass filter at 6.5khz.  Using this assumption, I'd expect
>to get a 6.5kHz sine wave at the output when the sensor is exposed to knock.

The ones we got from Volvo in 1979 and 1980 had diode AM detectors inside,
so we just ran it into a filter and then a schmitt gate.  The units from
Ford and GM wern't terribly frequency sensitive and didn't do as well as
the Volvo (resonant ceramic detector).

>I can't get engine under load to create knock, so I'm going to try using
>a speaker.

Did you try loosening the distributor and rotating in the advance direction
till pre-detonation is unavoidable? Maybe there is already some circuitry
functioning in this engine for just such a purpose. What engine is it?

>Does anyone know how these sensors operate and what the output is?

Like I mentioned above, it's been a few years. We were working on an
"optimizer" project and the knock sensor was refered to as a "de-optimizer"
since it was used to back off from whatever optimized timing advance we
had set. Fortunatly it wasn't a problem for the "optimized" blast furnaces
or gas-fired air conditioners/freezers.

>This is going to be connected to a microcontroller (68HC16) to help
>with fuel injection and spark timing.

I hate to mention that we did this with a 6502, but it worked, so what
the heck. That was about as advanced as we wanted to get, and the 6809
wasn't available in a noise-immune version yet.
Have fun!
Newsgroups: sci.electronics
From: kilian@cray.com (Alan Kilian)
Subject: What is an Induction resolver?
Date: 11 Apr 92 17:59:01 CDT

I have just made the rounds of the surplus electronics shops ans I came up
  with some interesting junk. One of them is a box with a motor and some gears
  connected to four "Induction resolvers".The trouble is I don't really know
  what an induction resolver is. There are two types: One with two coils
  on the rotor and two coils on the stator and a different one with two coils
  on the rotor and four coils on the stator.
The drawing on the side of the tings suggests that the coils on the rotor are
  crossed at a 90 degree angle and the coils on the stator for the two coil
  model are also crossed at a 90 degree angle. This suggests that if I put
  two different frequency signals in one side and listened on the other
  side I could determine the position of the shaft by comparing the
  amplitude of the signals coming out of the other two coils. The phase of
  the outputs would give you a non-ambiguous angle for the shaft. This
  sounds like a ton of trouble unless it's more accurate than a normal shaft
  encoder.
Now there is this other version with four coils on the stator and I just don't
  get that one.
These are made by American Electronics Incorporated Insturment Division in
  Culver City California. They were installed in a box made by Autonetics
  (A division of American Aviation, INC)
I think that this box has something to do with either a flight simulator or
  an autopilot. My Brother inlaw used to repair flight simulators for the
  Air Force and he showed me the insides of one and talked about rotating
  shafts to control the pitch etc. That was about 15 years ago so I didn't
  understand a thing he said. But now I can guess that you could rotate a
  shaft by the pitch of the simulator and read the resolvers to get things
  like lift and drag. Or maybe input the airspeed and get lift. By varying
  the gear ratios you would simulate another airplane. Sounds pretty 
  hard-wired but it could be possible. You should remember that this thing
  was made 3/10/64 (It's 2 days older than I am) so things like digital
  computers and A/D stuff was not available for any reasonable cost.

Well that's about it. The robot has reverse now and I'll post a new status
  this weekend.
                        -Alan Kilian
-- 
 -Alan Kilian         kilian@cray.com 612.683.5499 (Work) 612.729.1652 (Home)
  Cray Research, Inc.           | 
  655 F Lone Oak Drive          | 
  Eagan  MN,     55121          |
Xref: sparky sci.electronics:8565 comp.dsp:1135 sci.engr.biomed:261 sci.math:6090
From: francis@ircam.fr (Joseph Francis)
Newsgroups: sci.electronics,comp.dsp,sci.engr.biomed,sci.math
Subject: Re: quaternians, tracking, 3 dimensions
Date: 15 Apr 92 17:48:29 GMT
Organization: IRCAM, Paris (France)

In article <1992Apr14.173000.23478@pasteur.Berkeley.EDU> luzeaux@liszt.berkeley.edu (Dominique Luzeaux) writes:
>In article <1992Apr13.161433.25003@ircam.fr>, francis@ircam.fr (Joseph
>Francis) writes:
>|> I believe quaternions are rational extensions into threespace of
>|> imaginary numbers, you get from "x + iy" to "x + iy + jz" (or I guess
>|> for EE's, it would be "x + jy" and "x + jy + kz") where i,j have
...
>As wrote berrier@sweetpea.jsc.nasa.gov (K. Berrier 283-4125) in a previous
>article, a quaternion can be seen as a transformation matrix consisting of
>a scalar and a vector, where the scalar is the angle of rotation about
>the axis represented by the vector.

Duuuhh. The light goes on over my head. TX.



-- 
| Le Jojo: Fresh 'n' Clean, speaking out to the way you want to live
| today; American - All American; doing, a bit so, and even more so.
Newsgroups: sci.electronics,cmu.cs.robotics,comp.robotics
From: wtm@uhura.neoucom.edu (Bill Mayhew)
Subject: Re: Commodore help
Organization: Northeastern Ohio Universities College of Medicine
Date: Tue, 07 Apr 1992 03:38:33 GMT

The C-64 uses 9 VAC from the power pack to make some + and -
voltages internally.  I'd get a copy of the Commodore technical
reference; it's still available at many bookstores.  It shouldn't
be too hard to make a couple of little switcher supplies to supply
the needed voltages.

My fuzzy recollection is that the 60 Hz reference also went to one
of the 6526 pins, but I don't think anything in the operating
system cared about that.  The 9 VAC also goes out the the user port
pins, but if you don't have anything attached there, no matter.

It's been about 6 years since I did any work on a C-64, so
apologies if I got anything wrong.

Bill


-- 
Bill Mayhew      NEOUCOM Computer Services Department
Rootstown, OH  44272-9995  USA    phone: 216-325-2511
wtm@uhura.neoucom.edu   (140.220.1.1)
From: jon@sparcplug.et.iupui.EDU (Jon Burgoyne)
Newsgroups: sci.electronics
Subject: DC Shock
Date: 7 Apr 92 16:36:01 GMT
Article-I.D.: ethome.1992Apr7.163601.9749
Reply-To: jon@sparcplug.cadcam.iupui.edu
Organization: Purdue University, Indianapolis

I'm looking for a small circuit that could provide a shock to my dog.  This is
to build a collar similiar to the invisible fence product.  I believe they use
a 22.5v bat.

The RF part I can probably struggle through but producing a shock was not
something they taught us in school.

Any help appreciated.

Jon Burgoyne
Purdue University - Indianapolis
jon@sparcplug.cadcam.iupui.edu
Newsgroups: sci.electronics