Electrical Troubleshooting Guide; Power Supply On Smps Board - LG OK99 Service Manual

ELECTRICAL TROUBLESHOOTING GUIDE

1. POWER SUPPLY ON SMPS BOARD

No output 5.1VA
Is the F901 normal?
YES
Is BD901 normal?
YES
Is the VCC
(11 V ~ 25 V) supplied to IC901
pin4?
YES
Power line of MAIN PCB is short.
No 12 V
Is the
VCC 14 VA supplied to IC951
pin1?
YES
Is there
'H' signal at IC951
pin4?
YES
Check and replace IC951. Or check
line of MAIN PCB is short or not.
NO
Replace F901 (same fuse).
NO
Replace BD901.
NO
Is D960/ D961 normal?
Check or replace D960/ D961.
NO
Check or replace D963.
NO
Check PWR_CTRL
From DSP(IC501_D11).
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