Power Supply On Main Board - LG BP540N Service Manual

ELECTRICAL TROUBLESHOOTING GUIDE

3. POWER SUPPLY ON MAIN BOARD

No 3.3 V
Is the
Vcc supplied to D150
anode?
Is D150 output 5.3 VA?
Is there
signal at IC151
pin1?
Check IC151 and replace.
No 5 V
Is the
Vcc 5.3 VA supplied to IC150
pin27?
Is there
3.3 V at IC150
pin25?
Check IC150 and replace.
YES
YES
YES
YES
YES
YES
YES
NO
Check 5.3 VA on SMPS board.
NO
Check C178 or replace D150.
NO
Check voltage on IC501.
NO
Check 5.3 VA on SMPS board.
NO
Check PWR_CTL signal from IC501.
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