LG 28LM4 0B-PU Series Service Manual page 24

Standard Repair Process
Error
symptom
First of all, Check whether all of cables between board is inserted properly or not.
(Main B/D↔ Power B/D, LVDS or EPI Cable, Speaker Cable, IR B/D Cable,,,)
Y
No video
Normal
Normal audio
audio
N
Move to No Move to No
video/No audio
Precaution Precaution
A4 & A4 & A2 & A2
Always check & record S/W Version and White
Balance value before replacing the Main Board
A. Video error
No video/ Normal audio
A1
Check Back Light Y
On
On with naked eye
N
A18 Ch Check Power Board 12.5V output k P B d 12 5V
Normal
voltage g
N
Repair Power
Board or parts
Replace Main Board
- 24 -
Established
date
Revised date
A18
Check Power
Normal
Board
voltage
12.5V etc.
N
t t Repair Power R i P
Board or parts
Y Replace Inverter
or module
End
Re-enter White Balance value
1/13
Replace T-con/Main
Y
Board or module
2019