Repair Processes; A. Video Error; No Video/ Normal Audio - LG 42SL90QD Service Manual

Standard Repair Process
Error
LCD TV
symptom
First of all, Check whether all of cables between board is inserted properly or not.
(Main B/D↔ Power B/D, LVDS 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 ☞A7 & A4 ☞A7 & A4
Always check & record S/W Version and White
Balance value before replacing the Main Board
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Only for training and service purposes

A. Video error

No video/ Normal audio

☞A1
Check Back Light Y
On
On with naked eye
N
Check Power Board 20V or 24v output Ch k P B d 20V 24
☞A2
Normal Y
voltage g
N
Repair Power
Board or parts
Replace Main Board
Established
date
Revised date
☞A3
Check Power
Normal
Board
voltage
12v,5v etc.
N
t t Repair Power R i P
Board or parts
Replace Inverter
or module
End
Re-enter White Balance value
1
2008. 3 .26
1/13
Replace Main Board R l M i B d
Y
OR
Replace T-con
Board or module
☞A27 ☞A27
LGE Internal Use Only