Main Part; Main Electrical Troubleshooting Guide; Power (Dc-Dc Converter Circuit) - LG DP450G Service Manual

MAIN ELECTRICAL TROUBLESHOOTING GUIDE

1. POWER (DC-DC CONVERTER CIRCUIT)

A. NO POWER ON BY ADAPTOR
No power on
by ADAPTOR
YES
Is ADAPTOR
out 12V?
YES
Is D606 OK?
No +12V
NO
Is U401
3.3V OK?
YES Replace U401
NO
Is U202 1.8V OK?
Replace U202

MAIN PART

NO
Replace ADAPTOR
NO
Replace D606
No LCD_3.3V
No S3.3V
VCOM signal?
(Vip 4.5)
Replace U401
Replace U202
B. NO POWER ON BY BATTERY
No power on
by BATTERY
YES
Is BATTERY OK?
No A+5V
No M5V
VCC_5V
NO
Is U401
5V OK?
YES
NO
Is Q402 5V OK?
3-11
NO
Replace BATTERY
No 5VA
NO
Is U401
5V OK?
Replace U401