LG 55UJ634 Series Service Manual page 37

Standard Repair Process
symptom
First of all, Check whether all of cables between board is inserted properly or not.
(Main B/D↔ Power B/D, Vx1 Cable or EPI Cable, Speaker Cable, IR B/D Cable,,,)
No video Normal
Normal audio audio
N
Move to No
video/No audio
※Precaution ☞A4 & A2
Always check & record S/W Version and White
Balance value before replacing the Main Board
A. Video error
Error
No video/ Normal audio
☞A1
Y
Check Back Light
On with naked eye
☞A18
Panel Vcc (13V) output
☞A18
Y Check Power
On
Board +13V
N
Replace Inverter
Normal Y
or module
voltage
N
Repair Power
Board or parts
Replace Main Board
1
Established
date
Revised date
Y Replace T-con/Main
Normal
voltage Board or module
N
Repair Power
Board or parts
End
Re-enter White Balance value