LG SJ2 Service Manual page 29

ELECTRICAL TROUBLESHOOTING GUIDE
SMPS POWER CIRCUIT
No 3.3 VA
Check FB100 voltage 23 V.
Check IC100 voltage 5 V.
Check IC101 voltage 3.3 V.
Check 3.3 VA network, the device
a short circuit will cause no output.
No 1.2 VA
Check FB100 voltage 21 V.
Check IC100 voltage 5 V.
Check IC102 voltage 1.2 V.
Check 1.2 VA network, the device
a short circuit will cause no output.
YES
YES
YES
YES
YES
YES
YES
YES
NO
NO
NO
NO
NO
NO
3-6
Check SMPS.
Check IC100.
Replace IC101.
Check SMPS.
Replace IC100.
Replace IC102.