3-11
Copyright © 2008 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
MAIN PART
MAIN ELECTRICAL TROUBLESHOOTING GUIDE
No power on
by ADAPTOR
No +18V
No LCD_3.3V
No S3.3V
No A+5V
No M5V
VCC_5V
No 5VA
Replace ADAPTOR
NO
YES
1. DC-DC CONVERTER CIRCUIT
Is ADAPTOR
out 12V?
Replace D606
NO
YES
Is D606 OK?
Is U202 1.8V OK?
Replace U401
NO
Replace U202
NO
YES
Is U401
3.3V OK?
Is Q402 5V OK?
Replace U401
NO
Replace U202
NO
YES
Is U401
5V OK?
No power on
by BATTERY
Replace BATTERY
NO
YES
Is BATTERY OK?
Replace U401
NO
Is U401
5V OK?
A. NO POWER ON BY ADAPTOR
B. NO POWER ON BY BATTERY