LG 50LN54 Series Service Manual page 40

Standard Repair Process
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,,,)
No video
Normal
Normal audio
audio
N
Move to No
video/No audio
※Precaution ☞A6 & A3
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
Error
No video/ Normal audio
☞A1
Y
Check Back Light
On with naked eye
☞A2 Check Power Board 93.2~118.5V v output
☞A4
Y Check Power Board
On
24v, 12v,3.5v etc.
N
Replace Inverter
Normal Y
or module
voltage
N
Repair Power
Board or parts
Replace Main Board
Established
2013. 01 .09
date
Revised date
Y Replace T-con Board
Normal
or module
voltage
N
Repair Power Board
or parts
End
Re-enter White Balance value
1/14
LGE Internal Use Only