Video Error; No Video/ Normal Audio - LG 55LA7400 Service Manual

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
☞A7 & A3
※Precaution
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
Check Power Board 24v output
☞A2
☞A4
Y
Check Power Board
On
12v,3.5v etc.
N
Replace Inverter
Y
Normal
or module
voltage
N
Repair Power
Board or parts
Replace Main Board
- 40/83 -
Established
2012. 11 .30
date
Revised date
Y Replace T-con Board
Normal
or module
voltage
And Adjust VCOM
N
☞A28
Repair Power Board
or parts
End
Re-enter White Balance value
1/13
LGE Internal Use Only