High Voltage Failure - Samsung DP15HS/HT Service Manual

5-1-13 High Voltage Failure

IC401 Pin 6 OSC pulse exists?
3
Yes
Q402 Gate driving pulse exists?
10
Yes
Q402 Drain pulse exists?
11
Yes
Done
5-1-14 ABL Failure
Input full white pattern to monitor.
IC101 Pin 12 input exists and
varies with different patterns?
No
Check CN102.
No
T501 Pin 8 output exists?
Yes
IC201 Pin 26 output exists and
varies with different patterns?
Yes
Done
DP15H*/DP17L*
No
Check and replace IC401
and +12 V line.
No
Check and replace Q401.
No
Check and replace Q403,
L402.
Yes
Check and replace IC101.
No
Check and replace T501.
No
Check and replace IC201.
5 Troubleshooting
WAVEFORMS
3 2.00 V (IC401, #6)
CH1 P-P = 2.00 V CH1 RMS = 5.868 V
11 2.00 V (Q402, Gate)
CH1 P-P = 2.00 V CH1 RMS = 7.692V
11 50.0 V (Q402, Drain)
CH1 P-P = 50.0 V CH1 RMS = 73.7V
5-7