SPD3303C
Programmable Linear DC Power Supply
Service Manual
E01B

SPD3303C Service Manual1

Copyright 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 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 orconsequential in connection with the furnishing, use or performance of thismanual as well as any information contained.

2 SPD3303C Service ManualGeneral Safety Summary

Review the following safety precautions to avoid personal injuries and prevent
damages to this product or 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 productand approved by local state.
Avoid Electric Shock. To avoid injuries or losses of life, do not connect ordisconnect probes or test leads while they are connected 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 is grounded
correctly before connecting its input or output terminals.
Connect the Probe Properly. Do not connect the probe ground lead to a highvoltage 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 your manual for more
information about ratings before connecting.
Use Proper Fuse. Use only the specified fuse.
Do Not Operate Without Covers. Do not operate this instrument with covers
or panels removed.
SPD3303C Service Manual3

Avoid Circuit or Wire Exposed. Do not touch exposed junctions andcomponents when the unit is powered.
Do Not Operate With Suspected Failures. If you suspect damage occurs tothis instrument, have it inspected by qualified service personnel before
further operation. Any maintenance, adjustment or replacement especially tothe circuits or accessories should be performed by SIGLENT authorized
personnel.
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 condition.
Do Not Operate in an Explosive Atmosphere. To avoid injuries or fire
hazards, do not operate in an explosive atmosphere.

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 an injury or hazard may be accessible potentially.
CAUTION: Indicates damage to the instrument or other property may occur.
Symbols on the Product. These symbols may appear on the product:

4 SPD3303C Service ManualContent
Copyright and Declaration .............................................................................................. 2
General Safety Summary ............................................................................................... 3
Safety Terms and Symbols ............................................................................................ 4
Specification ................................................................................................................... 6
Performance Verification ................................................................................................ 8
Recommended Test Equipment .................................................................................. 8
Constant Voltage (CV) Test ......................................................................................... 9Constant Current (CC) Test ...................................................................................... 10
Assembly Procedures................................................................................................... 11
Security Consideration .............................................................................................. 11
Required Tools .......................................................................................................... 12
Disassembly Procedures .............................................................................................. 13
Troubleshooting ............................................................................................................ 22
Required Equipments ............................................................................................... 22Power Board Drawing ............................................................................................... 23
Main Board Drawing ................................................................................................. 24
Check the Power Board ............................................................................................ 25
Check the Main Board .............................................................................................. 27
Quick Guide for General Failures ................................................................................. 28
Maintenance................................................................................................................. 29
Contact SIGLENT ........................................................................................................ 30

SPD3303C Service Manual5Specification

Test conditions: warm-up for at least 30minitus, with temperature between+18℃~+28℃ and .
OutputRatings

CH1/CH2 independent

0～32V , 0～3.2A

CH1/CH2 series
CH1/CH2 parallel
CH3

0～64V , 0～3.2A
0～32V , 0～6.4A
2.5V/3.3V/5.0V , 3.2A

Constant
Line regulation
Voltage Mode Load regulation
Ripple and noise
Recover time
Temperature coefficient≤0.01%+3mV≤0.01%+3mV≤1mVrms（5Hz ～ 1MHz）≤50μs(50% load change ,minimum
load 0.5A)≤300ppm/℃

Constant
Line regulation
Current Mode Load regulation
Ripple and noise≤0.2%+3mA≤0.2%+3mA≤3mArms

CH3

Line Regulation
Load Regulation
Ripple and noise≤0.01%+3mV≤0.01%+3mV≤1mVrms（5Hz ～ 1MHz）

Tracking
Operation

Track error≤0.5%+10mV of Master(No Load)

Parallel Mode Line Regulation≤0.01%+3mV

Load Regulation≤0.01%+3mV

Line Regulation≤ 0.01%+5mV

Load Regulation≤ 300mV

Resolution

Voltage
Current

10mV
10mA

Display

Ammeter
Voltmeter
Program accuracy

3.2A full scale, 3 digits LED display
32V full scale, 4 digits LED display
Voltage：± (0.5% of reading + 2digits)
Current：± (0.5% of reading + 2digits)
Voltage：± (0.5% of reading + 2digits)
Current：± (0.5% of reading + 2digits)

Series Mode

Accuracy

Readback accuracy
Insulation

Case to terminal
Case to AC line

6 SPD3303C Service Manual

20MΩor above (DC 500V)
30MΩor above (DC 500V)

Power supply AC 100V/120V/220V/230V±10%, 50/60HZ
Size
275mm x 225mm x 136mm
Weight7.5kg

SPD3303C Service Manual7Performance Verification
Recommended Test Equipment
The test equipment instrumentation recommended for the performanceverification and adjustment procedures is listed below. If the exact instrument is
not available, substitute with the instrument of equivalent accuracy.
Instrument

Requirements

Recommended Model

DC voltage/current:
Digital Multimeter (DMM) accuracy: 100 ppm
Siglent SDM3055
resolution: 100 μV/μA
specification:
DC Electronic Load
SDL1020X
150V/30A/200W

Test Considerations
For optimum performance, all procedures should comply with the following
recommendations:⚫

Assure that the calibration ambient temperature is stable and between 18℃
and 28℃. Ideally, the calibration should be performed at 23℃±1℃.

⚫

Assure ambient relative humidity is less than 70%.

⚫

Allow a 30 minute warm-up period before verification or adjustment.

⚫ Keep the measurement cables as short as possible, consistent with the
impedance requirements.

The performance verification tests are recommended as acceptance tests
upon receipt of the instrument. The acceptance test results should becompared against the specifications given in chapter “Specification”. After
acceptance, repeat the performance verification tests at every calibrationinterval.
If the instrument fails performance verification, adjustment or repair is required.
8 SPD3303C Service ManualConstant Voltage (CV) Test
1. Set the DMM to measure DC voltage. Connect the DMM to the CH1(CH2)
output of the SPD3303C as shown below.

2. Turn on CH1(CH2) and change the current setting value to 0.1A.
3. Set the instrument to each output value described in the table below, thenverify the voltage readback value and measure the output voltage with the
DMM..
Output voltage setting

Output/Readback voltage limits

0 mV
100 mV
1V
10 V
25 V
30V

-20 mV ~ 20 mV
79.5 mV ~ 120.5 mV
0.975 V ~ 1.025 V
9.93 V ~ 10.07 V
24.855 V ~ 25.145 V
29.83 V ~ 30.17V

4. Compare the measured voltage to the spec range shown in the table above.

SPD3303C Service Manual9Constant Current (CC) Test
1. Set the DMM to measure DC current. Set the DC Electronic Load toconstant current mode and set the current value to 3.2A. Connect the DMM
to the CH1(CH2) output of the SPD3303C as shown below.

2. Turn on CH1(CH2) and change the voltage setting value to 30V.
3. Set the instrument to each output value described in the table below, thenverify the current readback value and measure the output current with the
DMM..
Output current setting

Output/Readback current limits

0 mA
100 mA
1A
2.5A
3A-20 mA ~ 20 mA
79.5 mA ~ 120.5 mA
0.975 A ~ 1.025 A
2.4675 A ~ 2.5325 A
2.965A ~ 3.035 A

4. Compare the measured current to the spec range shown in the table above

10 SPD3303C Service ManualAssembly ProceduresThis chapter describes how to remove the major modules from the SPD3303C
series generator. To install the removed modules or replace new modules,
please follow corresponding operating steps in reverse order.

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 power supply module.
To avoid electrical shock, disconnect the power cord from the generator, andthen wait at least three minutes for the capacitors in the generator to discharge
before beginning the disassembly.
Preventing ESD Almost all electrical components can be damaged byelectrostatic 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.
◆ Use only anti-static solder suckers.

SPD3303C Service Manual11Required Tools
Use these tools to remove or replace the modules in the generator:⚫

Anti-static gloves⚫

The multifunctional screwdriver or electric screwdriver⚫

Needle-nose pliers

12 SPD3303C Service ManualDisassembly Procedures

Step 1: Remove handle components
Remove the 2 PCS KM4 * 16 screw, handle fixed tablet (2 PCS) and handle.

handlehandle fixed tablet

SPD3303C Service Manual13

Step 2: Remove the metal plate
Remove 6 PCS screw on two sides, then remove the metal cover plate.

Metal cover plate

14 SPD3303C Service ManualStep 3: Remove the handle strut bone
Removed 4 PCS screws as shown in the figure below, and remove the strutbone according to the direction indicated by the arrow.

strut bone

SPD3303C Service Manual

15

Setup 4： Separate the front panel and the hardware components
Remove 4 PCS screws and the cables between the front panel and hardware
baseboard, remove the front panel and the power button.

Rear panel

Front panel

Hardware baseboard
Power button

Step 5: Remove the front panel components
Remove the 4 PCS screws, 7 PCS combination screw, screen ribbon cable on
the main control board, then the main control board, wave button cap and 7
PCS terminal can be removed; Remove 4 PCS screw between the metal front
panel and plastic shell, then the metal front panel can be removed; Remove 6
PCS screw on key board, then the key board can be removed

16 SPD3303C Service Manual

Main control board

Knob

Wave button cap

Terminal

SPD3303C Service Manual

17

Metal front panel

18 SPD3303C Service ManualKey board

Step 6: Remove hardware components
Remove 4 PCS screws and the cable between hardware rear pannel andhardware baseboard, then the hardware components can be removed

SPD3303C Service Manual19Hardware rear pannel

Hardware main components

Step 7: Remove hardware rear pannel components
Remove 6 PCS screws, then the power AC switch board and USB board
can be removed; Remove the 4 PCS screws, then the fan can be removed.
USB board

FanPower sea

Power AC switch board

Step 8: Remove hardware main component
Remove 10 PCS screws and the cables, then the small power board andpower switch board can be removed; Remove the 8 PCS screws, then thetransformer and floor mats can be removed.

20 SPD3303C Service ManualTransformer

Power board

Power switch board

Note:
To assemble the generator, please follow these same steps in reverse order.

SPD3303C Service Manual

21Troubleshooting

The internal structure of the SPD3303C Power Supply consists of power board,
main board and switching board, and they are linked through cables orconnectors. This chapter explains the main checking procedures for thesethree boards by measuring the rated test points on them, thus to help you
decide the reason for the failure you encounter while operating SPD3303C.

ESD Precautions
While performing any internal test of the SPD3303C, please refer to thefollowing precautions to avoid damages to its internal modules or components
result from ESD.
⚫ Touch circuit boards by the edges as possible as you can.
⚫ Reduce handling of static-sensitive modules when necessary.

.

⚫ Wear a grounded antistatic wrist strap to insulate the static voltage fromyour body while touching these modules.
⚫ Operate static-sensitive modules only at static-free areas. Avoid handling
modules in areas that allow anything capable of generating or holding astatic charge.

Required Equipments
The equipments listed in the table are required to troubleshoot the multimeter.
Table 5-1 required equipments
Equipment

Critical Specifications

ExampleAccuracy ±0.05%
Digital Multimeter

Siglent SDM3055
1 mV resolution

22 SPD3303C Service ManualPower Board Drawing

Power Board mainly works on rectifiers. Please refer to the following drawing
to quickly locate the test points on the analog board for easy resolution of the
failures you encounter.

SPD3303C Service Manual23

Main Board Drawing

Main board is used to control and manage the whole internal system of thePower Supply. It completes the GUI function, controlling and configuration
function for power board as well as man-machine interaction. Please refer tothe following drawing to quickly locate the test points on the main board foreasy resolution of the failures you encounter.

24 SPD3303C Service ManualCheck the Power Board
Here are procedures for testing the power board:
1. Several kinds of connectors including Fan Connector, Power Connector on
the power board. Check if all these connectors are connected properly.
2. Make sure that the connectors on the power board are properly connected,
then connect the SPD3303C to AC power and turn it on. Check if thevoltage values at all test points are within the spec range using a digital
multimeter. The voltage parameters to be tested are listed in table below:

Voltage Checking
Test the voltage points on the power board in the table below. If each tested
voltage value is within the corresponding spec range referring to the table
above, then the power board works normally. Otherwise, it proves to be faulted,
please return it to the factory to have it repaired or contact SIGLENT.

Table 5-3 Test DC voltages of the power board
Test point

Name

TP1

J202

TP2

J201

Test pin

Voltage (V)Error (V)

1 to 2

19.2 VAC±2

3 to 2

19.2 VAC±2

1 to 434.9 VAC±4

2 to 421.3 VAC±2.5

3 to 4

7.2

VAC

±1

TP3

J302

3 to 2+15 VDC

±0.5

TP4

J301

1 to 2

11.2 VAC±1.5

1 to 434.9 VAC±4

2 to 421.3 VAC±2.5

3 to 4

7.2

VAC

±1

1 to 2

19.2 VAC±2

3 to 2

19.2 VAC±2

2 to 1

+8

VDC

±1

1 to 2-15 VDC±0.5

3 to 2+15 VDC±0.5

1 to 2+15 VDC

±0.5

TP5
TP6

J101

J102

TP7

J702

TP8

JP205

TP8

JP103

SPD3303C Service Manual25

3 to 2

FUSE

F101

Good?

F201

Good?

F301

Good?

26 SPD3303C Service Manual-15 VDC

±0.5

Check the Main Board

Here are procedures for testing the main board:
1. Several kinds of connectors including Fan Connector and Power Connector
are located on the main board. Check if all these connectors are connected
properly.
2. Make sure that the connectors on the main board are properly connected,
then connect the SPD3303C to AC power and turn it on. Check if thevoltage values at all test points are within the spec range using a digital
multimeter. The voltage parameters to be tested are listed in table below:

Voltage Checking
Test the voltage points on the main board in the table below. If each tested
voltage value is within the corresponding spec range referring to the table
above, then the main board works normally. Otherwise, it proves to be faulted,
please return it to the factory to have it repaired or contact SIGLENT.
Table 5-4 Test DC voltages of the main board
Test point

Name

Pin

Voltage (V)Error (V)T1

UC1

3 to 1-15 VDC

±0.5

T2

UC2

3 to 2+15 VDC

±0.5

T3

J1

1 to 2

7.5 VAC±1

3 to 4

19 VAC±2

1 to 3+5 VDC±0.5

2 to 3+3.3 VDC

±0.2

T4
FUSE

U2
F1

Good?

SPD3303C Service Manual27

Quick Guide for General Failures

The general hardware failures are described in the following. Reading thefollowing information can help you quickly handle some easy hardware failureswith 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 burnt out. If the fuse needs to bechanged, please contact SIGLENT as soon as possible and return the
instrument to the factory to have it repaired by qualified personnel.
(4) Check if the power connector is properly connected to the main board
and power board.
(5) If the instrument still does not work normally, please contact SIGLENT.
2. The instrument starts up with a dark screen:(1) Check if the power connector is properly connected to 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 thescreen:(1) Check if the two end of the connector between the keypad circuit board
and the main board is properly connected.
(2) If the instrument still does not work normally, please contact SIGLENT.

28 SPD3303C Service Manual

Maintenance

Maintain Summary
SIGLENT warrants that the products it manufactures and sells are free fromdefects in materials and workmanship for a period of three years from the dateof shipment from an authorized SIGLENT distributor. If a product provesdefective 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 your nearest SIGLENT sales and service office.
Except that as provided in this summary or the applicable warranty Statement,
SIGLENT makes no warranty of any kind, express or implied, including without
limitation the implied warranties of merchantability and fitness for a particularpurpose. In no case shall SIGLENT be liable for indirect, special orconsequential damages.

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 at least 4 inches of compressible packaging material aroundall sides for the instrument. Use static-free packaging materials to avoid
additional damage to your unit.

SPD3303C Service Manual29

Contact SIGLENTSIGLENT Technologies Co., Ltd
Address：3/F, building NO.4, Antongda Industrial Zone, 3rd LiuxianRoad, Bao’an District, Shenzhen, P.R.China
Tel：+86-755-3688 7876
E-mail: sales@siglent.com
http://www.siglent.com

SIGLENT Technologies America, Inc

Address: 6557 Cochran Rd Solon, Ohio 44139
E-mail: info@siglent.com
http://www.siglentamerica.com

SIGLENT Technologies Germany GmbH
Staetzlinger Str. 70, 86165 Augsburg, Germany
E-mail: info-eu@siglent.com
Web: www.siglenteu.com

30 SPD3303C Service Manual