LG Electronics 42LT640H-ZA A. Video error, Lcd Tv, Check Back Light On with naked eye

Standard Repair Process

	Error	A. Video error	Established
LCD TV			date
	symptom	No video/ Normal audio	Revised date	1/13

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 audio

Normal Y audio

N

☞A1

Check Back Light On with naked eye

On Y

N

☞A4

Check Main Board 3.5V,12V,3.3V, 1.26V, 1.5V etc.

Normal Y voltage

N

Replace T-con Board or module

☞A28

Move to No video/No audio

☞A2 Check Power Board 24V,12V,3.5V output

Repair Power Board or parts

Normal Y voltage

N

Repair Power Board or parts

Replace Inverter or module

End

※Precaution ☞A7 & A3

Always check & record S/W Version and White Balance value before replacing the Main Board

Replace Main Board

Re-enter White Balance value

1

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