SDM3045X
Digital Multimeter
Service Manual
EN02D

Guaranty and Declaration
Copyright
SIGLENT TECHNOLOGIES CO., LTD All Rights Reserved.

Trademark Information
SIGLENT is the registered trademark of SIGLENT TECHNOLOGIES CO., LTD

Declaration⚫

SIGLENT products are protected by patent law in and outside of the P.R.C.

⚫

SIGLENT reserves the right to modify or change parts of or all the specifications or pricing
policies at company’s sole decision.

⚫

Information in this publication replaces all previously corresponding material.

⚫

Any way of copying, extracting or translating the contents of this manual is not allowed without
the permission of SIGLENT.

⚫

SIGLENT will not be responsible for losses caused by either incidental or consequential inconnection with the furnishing, use or performance of this manual as well as any information
contained.

Product Certification
SIGLENT guarantees this product conforms to the national and industrial standards in China as wellas the ISO9001: 2015 standard and the ISO14001: 2015 standard. Other international standard
conformance certification is in progress.

SDM3045X ServiceManual1General Safety Summary
Review the following safety precautions to avoid personal injury and to prevent damage to this productor any products connected to it. To avoid potential hazards, use this product only as specified.

Only qualified personnel should perform service procedures.

To Avoid Fire or Personal Injuries

Use Proper Power Cord.
Use only the power cord specified for this product and approved by the local regulating body.

Avoid Electric Shock.
To avoid injuries or losses of life, do not connect or disconnect probes or test leads while they areconnected to a voltage source.

Ground the Product.
This product is grounded through the protective terra conductor of the power line. To avoid electric
shock, the grounding conductor must be connected to the earth. Make sure the instrument isgrounded correctly before connecting its input or output terminals.

Connect the Probe Properly.
Do not connect the probe ground lead to a high voltage since it has the isobaric electric potential as
ground.

Observe All Terminal Ratings.
To avoid fire or shock hazard, observe all ratings and markers on the instrument and check yourmanual for more information about ratings before connecting.

Use Proper Fuse.
2

SDM3045X ServiceManualUse only the specified fuse.

Do Not Operate Without Covers.
Do not operate this instrument with covers or panels removed.

Avoid Circuit or Wire Exposed.
Do not touch exposed junctions and components when the unit is powered.

Do Not Operate With Suspected Failures.
If you suspect damage has occurred to this instrument, have it inspected by qualified service
personnel before any further operation. Any maintenance, adjustment or replacement especially tothe circuits or accessories should be performed by SIGLENT authorized personnel only.

Keep Product Surfaces Clean and Dry.

Do Not Operate in Wet/Damp Conditions.
To avoid electric shock, do not operate the instrument in wet or damp conditions.

Do Not Operate in an Explosive Atmosphere.
To avoid injuries or fire hazards, do not operate in an explosive atmosphere.

SDM3045X ServiceManual3Safety Terms and Symbols
Terms on the Product. These terms may appear on the product:

DANGER:

Indicates an injury or hazard that may immediately happen.

WARNING:

Indicates that there is potential for an injury or hazard.

CAUTION:

Indicates damage to the instrument or other property may occur.

Symbols on the Product. These symbols may appear on the product:

Hazardous
Voltage

4

Refer toInstructions

Protective
Earth Ground

ChassisGroundTest
GroundSDM3045X ServiceManualContents
1

2

General Features and Specifications........................................................................................ 7
1.1

General Features ............................................................................................................... 7

1.2

Specifications ..................................................................................................................... 8

Prepare Information .................................................................................................................. 12
2.1

3

4

5

Functional check .............................................................................................................. 12
2.1.1

Power-on Inspection ............................................................................................. 12

2.1.2

Default Setup......................................................................................................... 13

2.1.3

Self Test ................................................................................................................. 13

Performance Verification.......................................................................................................... 15
3.1

Performance verification test items .................................................................................. 15

3.2

Recommended Test Equipment ....................................................................................... 15

3.3

Performance verification step .......................................................................................... 16

3.4

Test Considerations.......................................................................................................... 16

3.5

Zero Offset Verification..................................................................................................... 16

3.6

DC Voltage and DC Current Gain Verification ................................................................. 17

3.7

4-wire Ohms and 2-wire Ohms Verification ..................................................................... 17

3.8

Frequency Accuracy Verification ...................................................................................... 18

3.9

AC Voltage and AC Current Verification .......................................................................... 18

3.10

Capacitance Verification................................................................................................... 19

Assembly Procedures .............................................................................................................. 20
4.1

Security Consideration ..................................................................................................... 20

4.2

Required Tools ................................................................................................................. 21

4.3

Disassembly Procedures ................................................................................................. 21

Troubleshooting ........................................................................................................................ 25
5.1

ESD Precautions .............................................................................................................. 25

5.2

Required Equipment ........................................................................................................ 25

5.3

Analog Board Drawing ..................................................................................................... 26

5.4

Main Board Drawing......................................................................................................... 26

SDM3045X ServiceManual

5

5.5

Check the Power Supply .................................................................................................. 27

5.6

Check the Analog Board .................................................................................................. 28

5.7

5.8
6

5.6.1

Voltage Check ....................................................................................................... 29

5.6.2

Analog board Clock Check.................................................................................... 29

Check the Main Board...................................................................................................... 29
5.7.1

Voltage Check ....................................................................................................... 30

5.7.2

Microprocessor Check .......................................................................................... 30

Quick Guide for General Failures .................................................................................... 31

Maintenance............................................................................................................................... 32
6.1

Maintenance Summary .................................................................................................... 32

6.2

Repackaging for Shipment ............................................................................................... 32

7

Contact SIGLENT ...................................................................................................................... 33

6

SDM3045X ServiceManual

1 General Features and Specifications
The SDM3045X is a multimeter with 4½ digit reading resolution and dual-display suited for any
application requiring high-precision, multifunction, and automated measurements. It features a
combination of basic measurement, multiple math, and display functions, etc.

1.1 General Features⚫

Real 4½ digit reading resolution⚫

Up to 150 rdgs/S measurement speed⚫

True-RMS AC Voltage and AC Current measurements⚫

1 Gb Nand Flash size, mass storage configuration files and data files⚫

Built-in cold terminal compensation for accurate thermocouple readings⚫

Includes EasyDMM PC software for easy control and data collection⚫

Built-in help system, convenient to acquire information⚫

Standard communication interfaces: USB Device, USB Host, LAN (Optional : USB-GPIB Adapter)⚫

USB & LAN remote interfaces support common SCPI commands.

⚫

Compatible with other popular DMMs on the market

SDM3045X ServiceManual71.2 Specifications
DC Characteristics
Accuracy ± (% of Reading + count) [1]Function

DC Voltage

DC Current

Resistance [3]Diode Test [6]Continuity Test

Range [2]600 mV
6V
60 V
600 V
1000 V [4]600 μA
6 mA
60 mA
600 mA
6A
10 A [5]
600 Ω
6 kΩ
60 kΩ
600 kΩ
6 MΩ
60 MΩ
100 MΩ
0~2V
2~4V
2000 Ω

Test current or
Load voltage< 33 mV< 330 mV
< 0.05 V< 0.5 V< 0.33 V< 0.6 V
1 mA
1 00 μA
10 μA
1 μA
200 nA
200 nA || 10 MΩ
200 nA || 10 MΩ
1 mA
1 mA
1 mA

Resolution
0.01 mV
0.0001 V
0.001 V
0.01 V
0.1 V
0.01 μA
0.0001 mA
0.001 mA
0.01 mA
0.0001 A
0.001 A
0.01 Ω
0.0001 kΩ
0.001 kΩ0.01 kΩ
0.0001 MΩ
0.001 MΩ
0.01 MΩ
0.0001 V
0.0001 V
0.1 Ω

Accuracy(one year; 23℃±5℃)
0.02+ 60.02+ 60.02+ 60.02+ 60.02+ 60.05+ 30.05+ 30.05+ 30.12+ 6
0.20+ 50.25+ 40.08+ 60.04+ 60.04+ 60.08+ 6
0.12+ 30.85+ 3
1.75+ 30.05+ 30.35+ 30.05+ 3

Remarks:[1] Specifications are for 0.5 Hour warm-up, “Slow” measurement rate and calibration temperature 18℃~28℃.
[2] 10% over range on all ranges except for DCV 1000 V, ACV 750 V, DCI 10 A and ACI 10A.
[3] Specifications are for 4-wire measure or 2-wire measure under “REF” operation.±0.2Ω of extra errors will be
generated if perform 2-wire measure without “REF” operation.
[4] Plus 0.02 mV of error per 1 V after the first ±500 VDC.
[5] 30 seconds OFF after 30 seconds ON is recommend foe the continuous current that higher than DC 7 A or AC
RMS 7 A.
[6] Accuracy specifications are only for voltage measuring at input terminal. The typical value of current under measureis 1 mA. Voltage drop at diode junction may vary with current supply. Adjustable voltage range: 0~4 V.

8

SDM3045X ServiceManualAC Characteristics
Accuracy ± (% of Reading + count) [1]Function

Range [2]600 mV

6V

True-RMSAC Voltage [3]

60 V

600 V

750 V

60 mA

600 mA
True-RMS
AC Current [5]6A

10 A [6]SDM3045X ServiceManualFrequency Range

Resolution

20 Hz – 45 Hz
45Hz – 100 Hz
100 Hz – 20 kHz
20 kHz – 50 kHz
50kHz –100 kHz
20 Hz – 45 Hz
45Hz – 100Hz
100 Hz – 20 kHz
20 kHz – 50 kHz
50 kHz –100 kHz
20 Hz – 45 Hz
45 Hz – 100 Hz
100 Hz – 20 kHz
20 kHz – 50 kHz
50 kHz –100 kHz
20 Hz – 45 Hz
45 Hz – 100 Hz
100 Hz – 20 kHz
20 kHz – 50 kHz
50 kHz –100 kHz
20 Hz – 45 Hz
45 Hz – 100 Hz [4]100 Hz – 20 kHz
20 kHz – 50 kHz
50 kHz –100 kHz
20 Hz – 45 Hz
45 Hz – 2 kHz
2 kHz – 10 kHz
20 Hz – 45 Hz
45 Hz – 2 kHz
2 kHz – 10 kHz
20 Hz – 45 Hz
45 Hz – 2 kHz
2 kHz – 10 kHz
20 Hz – 45 Hz
45 Hz – 2 kHz
2 kHz – 10 kHz

0.01 mV
0.01 mV
0.01 mV
0.01 mV
0.01 mV
0.0001 V
0.0001 V
0.0001 V
0.0001 V
0.0001 V
0.001 V
0.001 V
0.001 V
0.001 V
0.001 V
0.01 V
0.01 V
0.01 V
0.01 V
0.01 V
0.01 V
0.01 V
0.01 V
0.01 V
0.01 V
0.001 mA
0.001 mA
0.001 mA
0.01 mA
0.01 mA
0.01 mA
0.0001 A
0.0001 A
0.0001 A
0.001 A
0.001 A
0.001 A

Accuracy(one year; 23℃ ±5℃)
2.0 + 20
0.6 +10
0.3 + 20
2.0 + 40
3.0 + 102.0 + 20
0.6 + 10
0.8 + 20
2.0 + 40
3.0 + 40
2.0 + 20
0.6 +10
0.8 + 20
2.0 + 40
3.0 + 40
2.0 + 20
0.6 + 10
0.8 + 20
2.0 + 40
3.0 + 40
2.0 + 20
0.6 + 10
0.8 + 20
2.0 + 40
3.0 + 40
2.0 + 20
0.5 + 20
2.5 + 30
2.0 + 20
0.5 + 20
2.5 + 30
2.0 + 20
0.5 + 20
2.5 + 20
1.5 + 45
0.5 + 35
2.5 + 259

Additional wave crest factor error ( not Sine ) [7]
Wave crest coefficient
Error( % Range)
1-2
0.05
2-3
0.3
Remarks:[1] Specifications are for 0.5 Hour warm-up, “Slow” measurement rate and calibration temperature 18℃~28℃.
[2] 10% over range on all ranges except for DCV 1000 V, ACV 750 V, DCI 10 A and ACI 10 A.
[3] Specifications are for amplitude of sine wave input > 5% of range. For inputs from 1% to 5% of range and < 50 kHz,
add 0.1% of range extra error. For 50 kHz to 100 kHz, add 0.1% of range extra error.
[4] Plus 0.025 V of error per 1 V after the first ±400 VAC.
[5] Specifications are for sine wave input > 5% of range. 0.1% errors will be added when the range of input sine wave
is 1% to 5%.
[6] 30 seconds OFF after 30 seconds ON is recommend foe the continuous current that higher than DC 7 A or AC
RMS 7 A.
[7] For inputs Frequency Range < 100Hz

Frequency and Period Characteristics
Accuracy ± (% of Reading + count) [1]Function

Range

Frequency/Period

600mV to 750V [2]Frequency
Range
20 Hz – 2 kHz
2 kHz – 20 kHz
20 kHz – 200 kHz
200 kHz–500 kHz

Resolution

Accuracy( one year; 23℃ ±5℃)
0.01+30.01+20.01+20.01+2

Remarks:[1] Specifications are for 0.5 Hour warm-up.
[2] Except for special marks, the AC input voltage is 5% to 110% of range when <100 kHz and 10% to 110% of range
when >100 kHz. 750 V range is limited to 750 Vrms.
The accuracy is 10 times % of Reading when the measurement range of AC voltage is in 600mV range.

10

SDM3045X ServiceManualCapacitance Characteristic
Accuracy ± (% of Reading +count) [1]Function

Range [2]Max Testing Current

Resolution

Capacitance

2 nF
20 nF
200 nF
2 μF
20 μF
200 μF
10000 μF

10 μA
10 μA
100 μA
100 μA
1 mA
1 mA
1 mA

0.001 nF
0.01 nF
0.1 nF0.001 μF
0.01 μF
0.1 μF
1 μF

Accuracy(one year ;23℃ ±5 ℃ )
3+10
1+10
1+ 9
1+10
1+10
1+ 9
2+50

Remarks:[1] Specifications are for 0.5 Hour warm-up and “REF” operation. Using of non-film capacitor may generate additional
errors.
[2] Specifications are for from 1% to 110% on 2 nF range and ranges from 10% to 110% on other ranges.

Temperature Characteristics
Accuracy ± (% of Reading) [1]Function

Probe
Type
RTD [2]Temperature

TC [3]

Probe Model

Working
Temperature
Range

Accuracy(one year；
23℃ ±5℃)

α=0.00385
B
E
J
K
N
R
S
T

-200℃~660℃
20℃~1820℃-270℃~1000℃-210℃~1200℃-270℃~1370℃-270℃~1300℃-50℃~1760℃-50℃~1760℃-270℃~400℃

0.16℃
0.76℃
0.5℃
0.5℃
0.5℃
0.5℃
0.5℃
0.6℃
0.5℃

Temperature
coefficient
0℃~18℃
28℃~50℃
0.09℃
0.14℃
0.02℃
0.02℃
0.03℃
0.04℃
0.09℃
0.11℃
0.03℃

Remarks:[1] Specifications are for 0.5 Hour warm-up, not include probe error.
[2] Specifications are for 4-wire measure or 2-wire measure under “REF” operation.
[3] Built-in cold terminal compensation for thermocouple, accuracy is ±2℃.

SDM3045X ServiceManual112 Prepare Information
Before doing performance verifying or procedure adjusting, you should master the following
operations to make the multimeter work in a good state or deal with some simple functional problems.
The following contents are included in this chapter:⚫

How to perform functional checks⚫

How to use self-test routine⚫

How to recall factory Default settings

For more detailed information about multimeter operation, please refer to the User Guide for the
SDM3045X.

2.1 Functional check
This functional check covers three areas by which you can verify if the multimeter is working correctly.

2.1.1

Power-on Inspection

Before connecting the instrument to a power source, please select the AC voltage selector on the rear
panel of your multimeter according to the power supply. Then connect the power line to the socket on
the rear panel of the multimeter.

Note: To avoid electric shock, make sure that the instrument is correctly grounded to the earth
before connecting AC power.

The boot screen will appear after pressing the power-on button. To restore the instrument
configuration to factory default settings:
Press [Shift] > [Utility] > Store/Recall >Set To Defaults

12

SDM3045X ServiceManual

2.1.2

Default Setup

After setting to defaults, the multimeter should be set to DC voltage measurements. Other default
settings are shown in the following table

Default settings
Menu or System

DCV

AcquireMath

Display
Hold

2.1.3

OptionRange
Speed
FilterRel
Trg Src
Delay
Samples/Trigger
VMC Out
Statistics
LimitsdB/dBmRef Value
Display
Probe Hold

Default setting
Auto
Slow
Off
Off
Auto
Auto
1
Pos
Hide
Off
Off
Off
NumberOff

Self Test

The SDM3045X provides self-test functions, including Key Test, LCD Test, Beeper Test and Chip Test.

Operating Steps:
1. Press [Shift] > [Utility] > Test /Admin > Board Test
2. To test the keys:
Select Key to enter the key test interface. The on-screen lathy rectangle shapes represent thekeys on the front panel. Test all keys and knobs and you should also verify that all the backlit
buttons illuminate correctly.
3. To test the LCD screen:
Select LCD to enter the screen test interface, the screen shows the message:” Press ‘Change’
to change Press ‘Done’ to exit“. Press Change to start the test and observe if the screen has any
defects (missing pixels, for example).
SDM3045X ServiceManual13

4. To test the beeper:
Press Beeper to test the beeper. Under regular circumstances, pressing Beeper once and the
instrument will beep once.
5. Test the chips:
Press Chip > Start to start chip test. Determine whether the chip test passes according to theinterface message.

14

SDM3045X ServiceManual

3 Performance Verification
Use the performance verification tests in this section to verify the measurement performance of the
instrument using the instrument’s specifications listed in the product data sheet.

Performance verification tests are recommended as an acceptance test when you first receive theinstrument or after performing calibration. If the instrument fails performance verification, calibration
adjustment or repair is required.

3.1 Performance verification test items⚫

Zero Offset Verification⚫

DC Voltage and DC Current Gain Verification⚫

Frequency Accuracy Verification⚫

AC Voltage and AC Current Verification High Current Verification⚫

Capacitance Verification

3.2 Recommended Test Equipment
The recommended test equipment for the performance verification and calibration is listed below. If
the exact instrument is not available, substitute calibration standards of equivalent accuracy.

Application

Recommended Equipment

Zero Offset Verification

Keysight 34172B

DC Voltage and DC Current Gain Verification

Fluke 5522A

Frequency Accuracy Verification

Siglent SDG2000X Series Function/Arbitrary
Waveform Generator

AC Voltage and AC Current Verification

Fluke 5522A

Capacitance Verification

Fluke 5522A

SDM3045X ServiceManual153.3 Performance verification step
1. Connect the calibrator to the input terminals correctly.
2. Configure each function and range in the order shown in the table corresponding to the DMM
model number. Provide the input shown in the table.
3. Make a measurement and return the result. Compare measurement results to the test limits
shown in the table. (Be certain to allow for appropriate source settling time.)

3.4 Test Considerations⚫

Ensure that the test ambient temperature is stable and between 18°C and 28°C. Ideally thecalibration should be performed at 23°C± 2°C.

⚫

Ensure ambient relative humidity is less than 80%.

⚫

Allow a 30 minute warm– up period with a copper short connected.

⚫

Ensure the measuring rate is set to “slow” for DCV, ACV, DCI, ACI and 2-Wire/ 4-Wire Resistancemeasurements.

3.5 Zero Offset Verification

16

Input

FunctionOpen

DC Current

Short

DC Volts

Short

4-wire Ohms

Range
600 μA
6 mA
60 mA
600 mA
6A
10 A
600 mV
6V
60 V
600 V
1000 V
600 Ω
6 kΩ
60 kΩ
600 kΩ

Error from Nominal (1 year)±0.03 μA
±0.3 μA±3 μA±60 μA±500 μA±4 mA±60 μV±600 μV±6 mV±60 mV±600 mV±60 mΩ
±600 mΩ±6 Ω±60 Ω
SDM3045X ServiceManual

6 MΩ
60 MΩ
100 MΩ

±300 Ω
±3 kΩ
±30 kΩ

3.6 DC Voltage and DC Current Gain Verification
Input
Function

Voltage-600 mV
600 mV
-6 V
6V
10V
-60V
60V
-600V
600V
-500V
1000V

Range
600 mV

Error from Nominal(1 years)±180 μV

6V±1.8 mV±8 mV

DC Volts

Input
Function

60V±18 mV600V±180 mV

1000V±700 mV±800 mV

Range

Error from Nominal(1 years)

600 μA

600μA±0.33 μA

6 mA
60 mA
600 mA
6A
10 A

6 mA
60 mA
600 Ma6A
10 A±3.3 μA±33 μA±780 μA±12.5 mA
±29 mA

Current

DC Current

3.7 4-wire Ohms and 2-wire Ohms Verification
Input
Function

Range

Error from Nominal(1 years)

600 Ω

600Ω

±540 mΩ

6 kΩ
60 kΩ
600 kΩ
6 MΩ
60 MΩ
100 MΩ

6 kΩ
60 kΩ
600 kΩ
6 MΩ
60 MΩ
100 MΩ

±3 Ω
±30 Ω
±540 Ω
±7.3 kΩ±513 kΩ±1.78 MΩResistance

4-wire Ohms

2-wire Ohms

SDM3045X ServiceManual173.8 Frequency Accuracy Verification
Vrms
60mV
0.3V

Input
Frequency
490kHz
20Hz

Range
600mV
6V

Error from Nominal(1 years)±50 Hz±0.2Hz

3.9 AC Voltage and AC Current Verification
Vrms
600mV

6V
0.6V
6V

60V

300V

600V
750V
250V
75V

Irms
20mA
2mA
200mA
20mA

18

Input
Frequency
1kHz
50kHz
100 kHz
1kHz
50kHz
100 kHz
1kHz
1kHz
45kHz
20kHz
50kHz
100kHz
1kHz
50kHz
100kHz
1kHz
10kHz
1kHz
50kHz
100kHzInput
Frequency
1kHz
10kHz
1kHz
1kHz
10kHz
1kHz

Range
600mV

6V

60V

600V

750V

Range
60 mA

600 mA
6A

Error from Nominal(1 years)±2mV±12.4mV±18.1mV±50 mV±124 mV±184 mV±84.8mV±128 mV±1.22V±500 mV±1.24V±1.84V±5V±12.4V±18.4V±5V±12.4V
±6.2V
±5.4V
±3.4V
Error from Nominal(1 years)±0.12mA±0.54 mA
±0.41 mA
±1.2 mA±5.4 mA±6.1 mA

SDM3045X ServiceManual

1kHz
10kHz
1kHz
1kHz
10kHz

2A
200mA
10A

3.10

10 A

±14 mA±54 mA±26 mA±65 mA±270 mA

Capacitance Verification
Input
Capacitance
2 nF
20 nF
200 nF
2μF
20μF
200μF
10000μF

SDM3045X ServiceManual

Range
2 nF
20 nF
200 nF
2μF
20μF
200μF
10000μF

Error from Nominal(1 years)±0.07 nF
±0.3 nF±2.9 nF±30 nF±300 nF±2.9 μF±250 μF

19

4 Assembly ProceduresThis chapter describes how to remove the major modules from the SDM3045X. To install the removed
modules or replace new modules, please follow corresponding operating steps in reverse order.

4.1 Security Consideration
Only qualified personnel should perform the disassembly procedures. Whenever possible, disconnect
the power before removing or replacing. Otherwise, personal injuries or damages to the components
may occur.

Avoid Electric Shock Hazardous voltages exist on the LCD module and power supply module. To
avoid electrical shock, disconnect the power cord from the multimeter and then wait at least threeminutes for the capacitors in the multimeter to discharge before beginning the disassembly.

Preventing ESD Almost all electrical components can be damaged by electrostatic discharge (ESD)
during handling. Component damages can occur at electrostatic discharge voltages as low as 50
volts. The following guidelines will help preventing ESD damage when servicing the instrument or any
electronic device.
◆

Disassemble instruments only in a static-free work area.

◆

Use a conductive work area to reduce static charges.

◆

Use a conductive wrist strap to reduce static charge accumulation.

◆

Minimize handling.

◆

Keep replacement parts in original static-free packaging.

◆

Remove all plastic, foam, vinyl, paper and other static-generating materials from the immediate
work area.

◆

20

Use only anti-static solder suckers.

SDM3045X ServiceManual

4.2 Required Tools
Use these tools to remove or replace the modules in the multimeter:⚫

T10 hexagon screwdriver⚫

2# Phillips screwdriver⚫

Needle-nose pliers

4.3 Disassembly Procedures
1. Turn off the power and remove all measurement leads and other cables, including the power cord,from the instrument before continuing.
2. Rotate the handle to the upright position and remove it by pulling outward where it attaches to thecase.

3. Unscrew the four captive screws in the rear bezel and remove the foot pads as indicated by thearrow shown below.

SDM3045X ServiceManual21

4. Remove the screw on the bottom of the instrument and place it in a safe location for re-assembly.
Slide off the instrument cover as indicated by the arrow shown below.

5. Remove the cable plug (in the red circle and yellow box shown below) connected to the main
body.

22

SDM3045X ServiceManual

6. Unscrew the 5 captive screws in the rear metal cover and remove the rear metal cover.

7. Remove the cable plug connected to the front panel.

8. Remove the cable and unscrew all the screws then you can remove the PCBA.

SDM3045X ServiceManual23This concludes the disassembly procedure. To re-assemble the instrument, reverse the procedure.

24

SDM3045X ServiceManual

5 Troubleshooting
The internal structure of the multimeter consists of the analog board, main board and power supply
board, key and LCD board, and interface board. They are linked through cables or connectors. This
chapter explains the main procedures for checking the functionality of these three boards (mainly
main board and analog board) by measuring the corresponding test points and checking the signals
on specific connectors to help in determine the reason for the failure that has been encountered while
operating the SDM3045X digital multimeter.

5.1 ESD Precautions
While performing any internal test of the multimeter, please refer to the following precautions to avoid
damage to its internal modules or components resulting from ESD.
⚫

Only handle circuit boards by the board edges. Do not touch components or the board surface
with your fingers.

⚫

Reduce handling of static-sensitive modules when necessary.

⚫

Wear a grounded antistatic wrist strap to insulate the static voltage from your body while touchingthese modules.

⚫

Operate static-sensitive modules only at static-free areas. Avoid handling modules in areas thatallow anything capable of generating or holding a static charge.

5.2 Required Equipment
The equipment listed in the table is required to troubleshoot the multimeter.

Table 5-1 required equipment
Equipment
Digital Multimeter
Oscilloscope

SDM3045X ServiceManual

Critical Specifications
Accuracy ±0.05%; 1mV resolution
200 MHz Bandwidth

ExampleSiglent SDM3055
Siglent SDS2102X

25

5.3 Analog Board Drawing
The analog board is a signal sampling board that converts the analog input into a digital signal. It
mainly works on signal processing such as AC is converted to DC in order to measure AC magnitude.
Please refer to the following drawing to quickly locate the test points on the analog board for easy
resolution of the failures you encounter.

5.4 Main Board Drawing
The main board is used to control and manage the whole internal system of the multimeter. It
completes the GUI function, controlling and configuration function for analog board as well as manmachine interactions. Please refer to the following drawing to quickly locate the test points on themain board for easy resolution of the failures you encounter.

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SDM3045X ServiceManual

5.5 Check the Power Supply
There are two power connectors through which the analog board and main board can be supplied
electricity. For the analog board, there are three voltage test points on its power connector. For themain board, there is one test point.

Before performing the power supply testing procedure, please make sure that the multimeter isgrounded correctly through the protective lead of the power cord. Take care not to touch or evendisassemble the power supply module without any safety precautions, or you may probably sufferfrom electric shock or burn. Here are procedures for testing the power supply:
1. Disconnect the power cord of the multimeter and then check whether the fuse has been burnt out.
2. Remove metal shell of the multimeter using a driver, and then disconnect the power connector
connected to the main board.
3. Focus on the Power Connector for the analog board, which contains five pins from Pin 1 to Pin 5.
You can test the adjacent pins that are marked with Blue, Brown, Yellow and White to check
whether the AC voltage value is within the corresponding specified range using a digital multimeter.
The voltage parameters to be tested are listed in table below:

SDM3045X ServiceManual27

Table 5-2 Test AC voltages for the analog board power connector
Pins
Blue to Blue
Yellow to Brown
White to Yellow

Voltage value (V)81616

Error limit (V)
±1
±2
±2

Table 5-3 Test AC voltage for the main board power connector
PinsBlack to Black

Voltage value (V)8Error limit (V)±1

If each tested voltage value is within the corresponding spec range referring to the table above, thenthe power supply works normally. Otherwise, it proves to be faulted, please return it to the factory tohave it repaired or contact SIGLENT.

Note: The main power supply provides an input fuse to protect against the danger of fire in the eventof a failure of the power supply circuitry. However, this fuse will not fail ("open" or "blow") in normal
power supply operation except after a significant overload occurs. Replace the entire main power
supply assembly if the input fuse fails.

5.6 Check the Analog Board
If it is desired to remove the analog board from the metal shelf inside the multimeter, you’d better
place it on a clean, insulated mat. Here are procedures for testing the analog board:
1. Several types of connectors are used on the analog board. Check to make certain that all of these
are connected properly.
2. After checking these connectors, then connect the multimeter to AC power and power it on. Checkif the voltage values at all test points are within the specified range using a digital multimeter. The
voltage parameters to be tested are listed in table 5-3:

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SDM3045X ServiceManual

5.6.1

Voltage Check

Test the voltage points on the analog board in the table below. To locate the test points, please referto the drawing of the analog board. If not each tested voltage value is within the corresponding spec
range referring to table 5-4, it proves to be faulted, please return it to the factory to have it repaired orcontact SIGLENT.

Table 5-4 Test DC voltages of the analog board
Test point
T1
T2
T3
T4
T5
T6
T7
T8
GND

5.6.2

Name
Q3
Q1
U2
U3
U707
CA47
U710
U705
U705

Test pin
3
3
1
1
4
/
4
4
1

Voltage value (V)
-22
+22
-15
+15
+5
-3.8
+6.7
+3.3

Error limit(V)
±2
±2
±0.5
±0.5
±0.3
±0.3
±0.3
±0.2

Analog board Clock Check

Analog board clock is the internal system clock of the multimeter. To verify if the clock on the analog
board works normally, please test the clock frequency listed below using an oscilloscope.

Table 5-5 Clock Source of the analog Board
Test point
T9

Name
R24

Pin
1 or 2Frequency
12.8MHzStability±50ppm

5.7 Check the Main Board
If the main board does need to be removed from the metal shelf located inside the multimeter, place
it on a clean, insulated mat. Testing procedures for the main board are as follows:
1. Several types of connectors are located on the main board. Check if all these are connected

SDM3045X ServiceManual29

properly.
2. Make sure that the connectors on the main board are properly connected, then connect themultimeter to AC power and turn it on. Check if the voltage values at all test points are within the
spec range using a digital multimeter. The voltage parameters to be tested are listed in table 5-6:

5.7.1

Voltage Check

Test the voltage points on the main board in the table below. To locate the test points, please refer tothe drawing of the main board. If not each tested voltage value is within the corresponding spec range
referring to table 5-6, it proves to be faulted, please return it to the factory to have it repaired or contact
SIGLENT.

Table 5-6 Test DC voltages of the main board
Test point
TP1
TP2
TP3
TP4
GND

5.7.2

Name
J14
U14
U12
TP86
SC16

Pin
1 to 2
4
4
SolderVoltage value (V)
+8.6
+3.3
+5
+16

Error limit(V)
±2
±0.1
±0.2
±2

Microprocessor Check

Observe the LED light on the main board, which indicates the working state of microprocessor chip.
If the light turns on, then the corresponding codes have been loaded successfully and the chip is in
an operating state. Otherwise, there may be a problem with it.

30

SDM3045X ServiceManual

5.8 Quick Guide for General Failures
The general hardware failures are described in the following. Reading the following information canhelp you quickly handle some easy hardware failures with more convenience.
1. No start-up after pressing the Power button:
1)

Check if the power cord is correctly connected.

2)

Check if the power button is usable.

3)

Check whether the fuse has been burned out. If the fuse is blown, please replace with a fuseof the same rating.

4)

Check the connection between the power supply and the main board.

5)

If the instrument still does not work normally, please contact SIGLENT.

2. The instrument starts up with a dark screen:
1)

Check the connection between the keypad circuit board and the main board.

2)

If the instrument still does not work normally, please contact SIGLENT.

3. No response after pressing any button or abnormal display of the screen:
1)

Check the connection between the keypad circuit board and the main board.

2)

If the instrument still does not work normally, please contact SIGLENT.

SDM3045X ServiceManual31

6 Maintenance
6.1 Maintenance Summary
SIGLENT warrants that the products it manufactures and sells are free from defects in materials andworkmanship for a period of three years from the date of shipment from an authorized SIGLENT
distributor. If a product proves defective within the respective period, SIGLENT will provide repair or
replacement as described in the complete warranty statement.

To arrange for service or obtain a copy of the complete warranty statement, please contact yournearest SIGLENT sales and service office.

Except that as provided in this summary or the applicable warranty Statement, SIGLENT makes nowarranty of any kind, express or implied, including without limitation the implied warranties ofmerchantability and fitness for a particular purpose. In no case shall SIGLENT be liable for indirect,
special or consequential damages.

6.2 Repackaging for Shipment
If the unit needs to be shipped to SIGLENT for service or repair, be sure:
1. Attach a tag to the unit identifying the owner and indicating the required service or repair.
2. Place the unit in its original container with appropriate packaging material for shipping.
3. Secure the container with strong tape or metal bands.
If the original shipping container is not available, place your unit in a container which will ensure atleast 4 inches of compressible packaging material around all sides for the instrument. Use static-freepackaging materials to avoid additional damage to your unit32

SDM3045X ServiceManual

7 Contact SIGLENT
Headquarters:
SIGLENT Technologies Co., Ltd
Add: Bldg No.4 & No.5, Antongda Industrial Zone, 3rd Liuxian Road,
Bao'an District, Shenzhen, 518101, China
Tel: + 86 755 3688 7876
Fax: + 86 755 3359 1582
Email: sales@siglent.com
Website: int.siglent.com

North America:
SIGLENT Technologies America, Inc
6557 Cochran Rd Solon, Ohio 44139
Tel: 440-398-5800
Toll Free: 877-515-5551
Fax: 440-399-1211
Email: info@siglentna.com
Website: www.siglentna.com

Europe:SIGLENT Technologies Germany GmbH
Add: Staetzlinger Str. 70
86165 Augsburg, Germany
Tel: +49(0)-821-666 0 111 0
Fax: +49(0)-821-666 0 111 22
Email: info-eu@siglent.com
Website: www.siglenteu.com

SDM3045X ServiceManual33

About SIGLENTSIGLENT is an international high-tech company, concentrating on R&D, sales,
production and services of electronic test & measurement instruments.

SIGLENT first began developing digital oscilloscopes independently in 2002.
After more than a decade of continuous development, SIGLENT has extended

its product line to include digital oscilloscopes, isolated handheld
oscilloscopes,

function/arbitrary

waveform

generators,

RF/MWsignalgenerators, spectrum analyzers, vector network analyzers, digital multimeters,
DC power supplies, electronic loads and other general purpose test
instrumentation. Since its first oscilloscope was launched in 2005, SIGLENT
has become the fastest growing manufacturer of digital oscilloscopes. We
firmly believe that today SIGLENT is the best value in electronic test &measurement.

Headquarters:
SIGLENT Technologies Co., Ltd

Add: Bldg No.4 & No.5, Antongda Industrial
Zone, 3rd Liuxian Road, Bao'an District,
Shenzhen, 518101, China
Tel: + 86 755 3688 7876
Fax: + 86 755 3359 1582
Email: sales@siglent.com
Website: int.siglent.com

North America:
SIGLENT Technologies America, Inc
6557 Cochran Rd Solon, Ohio 44139
Tel: 440-398-5800

Toll Free: 877-515-5551
Fax: 440-399-1211
Email: info@siglentna.com
Website: www.siglentna.com

Follow us on
Facebook: SiglentTech

Europe:SIGLENT Technologies Germany GmbH
Add: Staetzlinger Str. 70
86165 Augsburg, Germany
Tel: +49(0)-821-666 0 111 0
Fax: +49(0)-821-666 0 111 22

Email: info-eu@siglent.com
34
Website: www.siglenteu.com

SDM3045X ServiceManual