Power Supply On Main Board - LG BH5140S Service Manual

ELECTRICAL TROUBLESHOOTING GUIDE

3. POWER SUPPLY ON MAIN BOARD

No 3.3 V.
Is the VCC 3.7 VA supplied to IC155 pin3?
Is there 'H' signal at IC155 pin2?
Check IC155 and replace.
No 5 V.
Is the VCC 6 VA supplied to IC152 pin2?
Is there 'H' signal at IC152 pin1?
Check IC152 and Replace.
No 1.2 V.
Is the VCC 14 VA supplied to IC153 pin8?
Is there 1.2 V at IC153 pin9?
Check IC153 and replace.
No 1.5 V.
Is the VCC 14 VA supplied to IC153 pin13?
Is there 1.5 V at IC153 pin12?
Check IC153 and replace.
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
NO
Check 3.7 VA on SMPS Board.
NO
Check IC101 pin58 (DCDC33_CTRL).
NO
Check 6 VA on SMPS Board.
NO
Check IC101 pin68 (LDO_CTRL).
NO
Check 14 VA on SMPS Board.
NO
Check IC101 pin60 (DCDC12_CTRL).
NO
Check 14 VA on SMPS Board
NO
Check IC101 pin59 (DCDC15_CTRL).
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