Samsung SyncMaster 755DF - Video and Display Quality Issues

5 Troubleshooting
SyncMaster 753DF/755DF 5-7
5-1-13 High Voltage Failure
IC401 Pin 6 OSC pulse exists?
Q402 Gate driving pulse exists?
Check and replace Q401, Q423.
Yes
Yes
No
Check and replace IC401
and +12 V line.
No
Q402 Drain pulse exists?
Check and replace D401, Q403,
L402.
Yes
No
Done
WAVEFORMS
10
3
11
2.00 V (Q402, Gate)
CH1 P-P = 2.00 V CH1 RMS = 7.692V
3
2.00 V (IC401, #6)
CH1 P-P = 2.00 V CH1 RMS = 5.868 V
11
50.0 V (Q402, Drain)
CH1 P-P = 50.0 V CH1 RMS = 73.7V
IC101 Pin 8 input exists and
varies with different patterns?
Check and replace IC101.
Input full white pattern to monitor.
No
Yes
No
T501 Pin 8 output exists?
Check and replace T501.
Yes
No
IC201 Pin 26 output exists and
varies with different patterns?
Check and replace IC201.
Yes
No
Done
Check CN102.
5-1-14 ABL Failure
11