Samsung Syncmaster 743b Service Manual

4-3
4. Troubleshooting

4-2-1. Circuit diagrams when the power does not turn on
 

4-4 
4. Troubleshooting

4-3. When the screen is blank (Analog)
Symptom- LEven though the LED power turns on, the screen is blank when connecting the VGA cable.
Major checkpoints
- Even though the LED power turns on, the screen is blank when connecting the VGA cable.
- Check the D-sub cable connections.
- Check whether the LVDS cable is connected correctly to the panel.
- Check whether the lamp connector of the panel is connected correctly to the IP board.
CN 400
X 201IC 200
R111, R114, R118...

4-5
4. Troubleshooting

4-3-1. When a blank screen is displayed (Analog)
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4
②
①
 

4-6 
4. Troubleshooting

4-3-2. Waveforms when no screen is displayed (Analog) 
①
④
③
 

4-7
4. Troubleshooting

4-4. Error Examples and Actions
Error AppearanceSymptoms and ActionsRemarks
Symptom: DVI signals are not recognized.
Cause:  This error occurs because the PC cannot 
recognize the mode information since the 
DVI DDC is not input to the monitor.
Action:  Input the DVI DDC.
*On how to input DDC, refer to the 
training manual.
Symptom:  A full white screen is displayed regardless of 
the signals when turning on the monitor.
Cause:  This error occurs when only lamp power 
is supplied...

4-8 
4. Troubleshooting

4-5. Adjustment
4-5-1. Service Adjustment Conditions
Precautions before a Service Adjustment 
1) Check whether the devices for the service adjustment are operating normally. 
2) Secure a space that is sufficiently wide for disassembling the monitor. 
3) Prepare a soft mat on which the monitor will be disassembled.
Entering Service Mode 
Entering:MenuBrightness 0Contrast 0Hold down the Enter button for five (5) seconds.
Exiting:Power OFFPower ON
Basic Service Items to Perform...

4-9
4. Troubleshooting

4-5-2. Service Function Specifications
Checking the Code Version
1. Check the MCU code version and checksum after entering SVC Mode.
2.   Entering SVC Mode
 
- Adjust the Brightness and Contrast values to 0. 
- Hold down the Enter button for five (5) seconds. 
- The SVC Function OSD is displayed. 
- To exit the SVC Function, turn the power off.
3.   
Safe Mode
 
-   
When the input signal is higher than the supported frequency of the product, safe mode gives users some time (one...

4-10 
4. Troubleshooting

2. Press the - button to change the setting to On or Off.
When replacing the panel
After replacing the panel, move to the Panel item and hold down the Menu button for five (5) seconds. 
The Ch. No is incremented by 1 and then both the On Time and Cycle are set to 0.

This number is incremented by 1.
 

4-11
4. Troubleshooting

Inputting the DDC Data
Use the DDC Manager MTI-2050 version or later.
1) Click the Open [F5] icon. 
2) Select a port. 
3) Open a DDC file. 
4) Select a date and click the OK [Save] button. 
5) Click the Next [OK] button. 
6) Enter the serial number and then press the Enter button 
When inputting digital data after inputting analog data, repeat steps 2 \
to 5.
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※
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2
3
4
5
6
 

4-12 
4. Troubleshooting

Inputting the MCU Data
1) Check the following options. 
 - Manufacture: MSTAR 
 - Device Type:TSUM16_ROM128K_ext_flash 
 - Communication Port: DSUB15 (Analog) 
 - External Memory: PMC25LV010E 
2) Click the LoadFile button, select an MCU code file, and then click the Open [O] button.
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