LG 47LA620V Same LED Failing Back Light Issues

[jdawg99]

Hi All,

I need some help with this one please. I am attempting a repair on the backlight. TV turns on and flashes the LG logo so stripped it down and found one faulty LED. Replaced it and tested on an LED tester and the strip was good. Put it back onto the PSU and it lasted about 20 seconds before going out again. Same LED had blown. Changed it for another type of SMD one (same voltage) and it seemed fine. Put the TV back together but it was quite dim. Noticed it was in power save mode so turned it off and the screen was bright. Left it on for half an hour only to come back to the same bloody LED blown. Seems odd that this is the 3rd LED in the same place in the same strip to blow. I've had similar issues on another TV and found a mod to reduce the current going to the backlight and this sorted that but with this PSU board (Vestel EAX64905501) I'm not sure how to do it.

Any advice guys?

[Diah]

Re: LG 47LA620V Same LED Failing Back Light Issues

no need any mode... just BL level bring it down to 59% .... also you put wrong SMD LED.. it should 4.7V build in zener diode

[jdawg99]

Re: LG 47LA620V Same LED Failing Back Light Issues

it should 4.7v build in zener diode

4.7?

[Donny2derby]

Re: LG 47LA620V Same LED Failing Back Light Issues

I’ve bid on the same make and model with the same fault described as above.

What would be the correct way to diagnose and repair? Replace the suspect diode with a 4.7v zener diode then drop the backlight down to 57%?

Exciting times!

[jdawg99]

Re: LG 47LA620V Same LED Failing Back Light Issues

Anyone have a link to the correct SMD led that I should be using please.

[Diah]

Re: LG 47LA620V Same LED Failing Back Light Issues

read this old threat you will find link too

[Davi.p]

Re: LG 47LA620V Same LED Failing Back Light Issues

i have fixed the same model by replacing some leds, if i remember was 3,7v, i don't know the watts, must match also that.. sorry no notes in the file, maybe when im on pc i find it in the emails

[jdawg99]

Re: LG 47LA620V Same LED Failing Back Light Issues

Thanks all, I will get some on order, hopefully it was just because I used the wrong spec LED.

[jdawg99]

Re: LG 47LA620V Same LED Failing Back Light Issues

Thanks all, I will get some on order, hopefully it was just because I used the wrong spec LED.

Just an update, it was the wrong spec led. Ordered some marked for LG tv's and it worked fine.

[sigmeyer]

Re: LG 47LA620V Same LED Failing Back Light Issues

As someone who does these jobs daily , if you are going to an extent of opening the tv with removing the screen , you should replace the whole set of strips . Soldering by hand is not a good technique, and you will have problems. This is tested and tried by me .. Always replace whole strips as a unit , if you want to have some serious success with this... otherways i wouldnt really bother