SDL1000X Troubleshooting Manual

ESD Precautions ............................................................................................................... 2
Required Equipment ........................................................................................................ 2Main Board Drawing ........................................................................................................ 3
Check the Power Supply ................................................................................................ 4
Check the Analog Section .............................................................................................. 4
Voltage Checking.......................................................................................................... 5
Analog Section Clock Checking ............................................................................... 5
MCU Checking ............................................................................................................... 5
Check the Digital Section ............................................................................................... 6
Voltage Checking.......................................................................................................... 6Digital Section Clock Checking ................................................................................ 6
CPU Checking................................................................................................................ 6Quick Guide for General Failures ................................................................................. 7

Troubleshooting
The internal structure of the electronic load consists of the main board and thekeyboard and they are linked through cables or connectors. This chapter
explains the main troubleshooting procedures for the main board by measuring
the rated test points on them. This will help to determine the reason for thefailure encountered while operating SDL1020X.

ESD Precautions
While performing any internal test of the electronic load, please refer to thefollowing precautions to avoid damages to its internal modules or components
resulting from ESD.
Touch circuit boards by the edges whenever possible.

Limit handling of static-sensitive modules whenever possible.

Wear a grounded antistatic wrist strap to help drain the static voltage from.

your body while touching these modules.


Operate static-sensitive modules only in static-free areas. Avoid handling
modules in areas that allow anything capable of generating or holding astatic charge.

Required Equipment
The equipment listed in the following table are required to troubleshoot theelectronic load.
Table 5-1required equipments
Equipment

Critical Specifications

ExampleAccuracy ±0.05%

SDM3055

Digital Multimeter
1 mV resolution
Oscilloscope

200 MHz BandwidthSDS2102X

Main Board Drawing
The main board consists of power, analog and digital sections:1）、Power section：110/220 V is converted to a low voltage to supply the analog
and digital sections.
2）、Analog section：Used primarily in the functions of CC、CV、CR、CP, etc.
3）、Digital section：Responsible for data processing, function control、and LCD
display control.

Check the Power Supply
Both the analog and digital sections have a power connector and we cancheck whether the input voltage is within the rated specification. Before
performing the power supply testing procedure, please make sure that theelectronic load is grounded correctly through the protective ground lead of thepower cord. Take care not to touch or even disassemble the power supply
module without following safety precautions, or electric shock or burn may
occur. Following are the procedures for testing the power supply:
1. Disconnect the power cord of the electronic load and then check whether
the fuse has been burned out.
2. Remove metal shell of the electronic load using a driver, and thendisconnect the power connector.
3. Locate the power connector for the analog section, which contains five pins,from Pin 1 to Pin 5. You can test the adjacent pins, using a digital multimeter,
hat are marked with blue, brown, yellow and white to check whether the ACvoltage values are within the corresponding specified range. The voltage
parameters to be tested are listed in table below:
Table 5-2: Test AC voltages on the analog section power connector
Pins

Voltage (V)Error (V)blue to blue

8±1Yellow to brown

16±2White to yellow

16±2

Table 5-3: Test AC voltage for the digital section power connector
PinsVoltage (V)Error (V)Black to black

12±2If each tested voltage value is within the corresponding spec range, as listed in
the table above, then the power supply is operating normally. If not, it is most
likely defective. Please return it to the factory for repair or contact SIGLENT.
Note: The main power supply is protected by an input fuse in order to guard
the unit if any major failure was to occur. However, this fuse will not fail ("open"or "blow") in normal power supply operation except when and if a significant
overload occurs. Replace the entire main power supply assembly if the input
fuse fails.

Check the Analog Section

To prevent any components or assemblies on the main board from being
damaged or overheated it is essential to cool the main board wheneverpossible using a fan. Here are procedures for testing the main board:
1. Several kinds of connectors including the Fan Connector, Power Connectorand Keypad Connector are located on the main board. Check to makecertain all these connectors are connected properly.
2. Make sure that the connectors on the channel board are properly connected,
then connect the electronic load to AC power and power it on. Check if thevoltage values at all test points are within the specified range using a digitalmultimeter. The voltage parameters to be tested are listed in the tablebelow:

Voltage Checking
Test the voltage points in the analog section and compare to the table below. If
each tested voltage value is within the corresponding specified range thenthe analog section is operating normally. If not, it is most likely defective,
Please return it to the factory for repairor contact SIGLENT.
Table 5-3 Test DC voltages of the analog board
Test point

Name

Test pin

Voltage (V)Error (V)T1

U18

3+15±1T2U19

3-15±1T3U93+5±0.25

T4U92 or 4+3.3±0.065

T5UB116+2.5±0.0025

T11AGND

10/Analog Section Clock Checking
The Analog section clock is the internal system clock for the electronic load. To
verify if the clock on the analog section is working normally, please test theclock frequency listed below using an oscilloscope.
Test point

NamePinFrequency

StabilityT6RD60

1 or 225 MHz±50 ppm

MCU Checking

Look at the LED light on the analog section. It indicates the working state ofthe MCU. If the light flashes at a certain frequency, then the corresponding
codes have been loaded successfully and the MCU is operating correctly If not,it may be defective.

Check the Digital Section
Voltage Checking
Test the voltage points in the digital section to the table below. If each tested
voltage value is within the corresponding specified range then the digital
section is operating normally. If not, it is most likely defective.Please return it tothe factory for repairor contact SIGLENT.
Test point
T7

Name

Test pin

Voltage (V)Error (V)

U5

8

3.3

±0.065

Digital section Clock Checking
To verify if the clock in the digital section is working correctly, please test theclock frequency and compare to the value listed below using an oscilloscope.
Test point

Name

PinFrequency

Stability

T8R18

1 or 225 MHz±50 ppm

CPU Checking
There is no status light in the digital section to indicate the working status ofthe CPU，We can check if the CPU and MCU are communicating. If so, theCPU is operating normally. Please view the communication signals listed
below using an oscilloscope.
Test point

T9T10Name

U6SC8PinSignal

3

SPI_CS

4SPI_SCK5

SPI_MOSI6

SPI_MISO1

DGND

Quick Guide for General Failures
Three general hardware failures are described in the following list. Referring tothis information can help you quickly locate some of the more readily
diagnosed failures.
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 working correctly.
(3) Check whether the fuse has been burned out. If the fuse needs to be
replaced please contact SIGLENT as soon as possible and return theinstrument to the factory to have it repaired by qualified personnel.
(4) Check if the power connector is properly connected to 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 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 ends of the connector between the keypad circuit board
and the main board are properly seated.
(2) If the instrument still does not work normally, please contact SIGLENT.