LG CM9750 - ELECTRICAL TROUBLESHOOTING GUIDE

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ELECTRICAL TROUBLESHOOTING GUIDE
1. POWER SUPPLY ON SMPS BOARD
YES
YES
YES
YES
YES
No output 5.6 VA
No 12 V
Power line of MAIN PCB is short.
Replace F901 (same fuse).
Check or replace D962.
Is D960/ D961 normal?
Replace BD901 or BD902.
Check P_CTL from μ-com.
Check and replace IC951.
Or check line of
MAIN PCB is short or not.
Check or replace D960/ D961.
NO
NO
NO
NO
NO
Is the F901 normal?
Is the
VCC 13 VA supplied to IC951
pin2?
Is the VCC
(11 V ~ 25 V) supplied to IC901
pin4?
Is BD901 or BD902 normal?
Is there
‘H’ signal at IC951
pin1?