LG 49UF771V Service Manual page 67

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 Cable, Speaker Cable, IR B/D Cable,,,)
No video
Normal
Normal audio
audio
Move to No
video/No audio
※Precaution ☞A4 & A2
Always check & record S/W Version and White
Balance value before replacing the Main Board
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A. Video error
No video/ Normal audio
☞A1
Y
Check Back Light
On with naked eye
N
Check Power Board 24V output
☞A18
☞A18
Y Check Power
On
Board
24V, 12V,3.5V etc.
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
Board or module
voltage
And Adjust VCOM
N
Repair Power
Board or parts
End
Re-enter White Balance value
1/16
LGE Internal Use Only