Lg 65UB950V No Image

[nomoresonys]

Re: Lg 65UB950V No Image

there's some testing on a samsung, probably lots more on youtube: https://www.youtube.com/watch?v=rNqRZ2qaDJY

[nomoresonys]

Re: Lg 65UB950V No Image

Some testing there to look at, only throwing it up because of the testing info, not saying you should buy their tester, it's oos anyway: https://www.youtube.com/watch?v=4RzuLiRTzJg

[nomoresonys]

Re: Lg 65UB950V No Image

https://www.youtube.com/watch?v=EgRKJAqYqeo

[nomoresonys]

Re: Lg 65UB950V No Image

One for an lg there, pretty much giving the same info, pretty easy to follow: https://www.youtube.com/watch?v=6hQOiN4-XPk

[Megaule]

Re: Lg 65UB950V No Image

So i demount the complete tv/panel... And the strange thing is that only 3 of 12 led "areas" go on when i make the stand alone test of the power supply. But the other led areas are good because i told the molsfet and give them ground with a bridge... And they work !! But the mosfets are not switching the gnd when i make the test... Only 3 of them... But voltage on gate it is!!!

[Megaule]

Re: Lg 65UB950V No Image

This are the mosfet area on the pwrboard with the led driver, i told all the mosfets, only remains is in place, an one 1 connected with bridges... Thisone in place works... The other not...

[Megaule]

Re: Lg 65UB950V No Image

Attached file

[nomoresonys]

Re: Lg 65UB950V No Image

Not sure what you are doing, if you have backlights out, they are likely bad, you can test them a few ways now that you have them uncovered, one of the easiest is rig up some 9 volt batteries and test the strips, many videos on youtube covering it. If you do test them with batteries be sure backlights are unplugged from the powerboard.

[Megaule]

Re: Lg 65UB950V No Image

Hi, i had tested the backlights... They are good!!! But when i plug in the board, (pwron and drvon with 1k resistor on 3,5v) then the board will give me the 12v and 24v. Also the 80v for backlight i get, but only for 3 seconds, the the 80v go out. And only 3 of the mosfets switched the backlights on (3 of 12) all the other mosfet do not switch!! There must be a problem with the led driver ic!

[nomoresonys]

Re: Lg 65UB950V No Image

Maybe test all the mosfets for shorts, make sure none of the 3 pins shows continuity to the other 2 pins of the mosfet.

[seb59]

Hello.
I'm exactly the same problem wih my LG 65UB950V.
I have the 3,5v standyby, when i power on the tv i have also the 12v and 24v!
the 12v for tcon supply is missing
NO backlight (backlights turn on when i put 3.5V on DR-ON et P-DIMM 1 &2 but no image)
A led on power supply board flash 5 times
Etc…

I suppose that the problem is the mainboard…

[seb59]

Hi
I tried the An-Klamm's method
I heat the yellow marked area and then I test it.
If that works, then you can let it cool down completely and try only one IC etc. Then you can narrow it down.
NOW, The backlights turn on, and i have 12V on the Tcon too, the led on power supply board didn't flash.

but NO IMAGE....
an idea?

[Secuman]

Hello, has anyone found a final solution to the repair?

[Davi.p]

Hi, a lot of confusion here, i suggest you to open your ownn thread, first need to test PSB alone with dummy loads, thern test PSB + backlights, then if ok possibly the main board also, LG are VERY very usual for BGA problems..