LG SN4A - Page 50

3-21
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ELECTRICAL TROUBLESHOOTING GUIDE
No D_3.3V
PWM_3.3V
Check F301 Voltage 25 VA
Check FB305 Voltage 5.1 V A
Check Adapter
Replace IC305
YES
YES
YES
NO
NO
Check R371 Voltage 12 VA
Check R373 Voltage 3.3 VA
Check FB307, FB313 Voltage 3.3 V
Replace IC302
Replace IC301
Replace IC304
YES
YES
YES
NO
NO
NO
OK
ADAPTER POWER CIRCUIT