Black Screen And Backlight Turn On - Samsung 720N Service Manual

4 Troubleshooting

4-6 Black Screen and backlight turn on

Black Screen
Check power
supply: Pin1, 2 of
CN101
Yes
Check pin34, 51,
66, and 82 Of
U105
Yes
Check pin32, 49,
56, and 75 Of
U105
Yes
Check Reset
(pin84) Of U105
Yes
Check Crystal:
Pin96, Pin97 Of
U105
Yes
Check CCFL-
Enable (pin85) of
U105
No
MCU Fail
4-6
No
No
No
No
No
Yes
Check pin5 of
CN101
No
Power Fail
Check FB103 And U102
Check FB106 And U101
Check C144, R172
Check: X101, C153,
C154
Yes
Inverter Fail
Check R167, Q106,
R108, R110