Samsung UE 50 RU7092 restart

[peterkos2]

Good day.
If you can advise me on such a problem.
TV Samsung UE 50RU7092 not even biennial.
Main Board BN41-02703A
Power board BN44-00932Q
Panel+T-Con BN96-45763A

When I plug it into the socket, the backlight turns on, dims, lights up and then restarts it. I thought the backlight was faulty, but when I unplug the mainboard, the backlight goes full.
When I leave it overnight without juice and turn it on in the morning, sometimes the logo pops up and then the menu, after a while the image shakes and disappears a bit and again without the image restarts - during restarts there is a sound, the image does not.
I tried to disconnect one strip from the screen, and turned on- the sound went but the picture does not but responds to the DO buttons to hear that I'm in the menu, not even half of the screen goes, still the same.
The mainboard I have a spare from 43RU and the HW is almost the same but when I replaced it, it is still the same
If you could advise if you have the time.
well thank you

[ducky29]

Re: Samsung UE 50 RU7092 restart

Its probably a bad panel or ribbon cable that connects the mainboard to the panel. First look for physical damage on the ribbon cables. Also check for shorts on the panel pcb or any overheating component.

[Davi.p]

Re: Samsung UE 50 RU7092 restart

In theese Samsung bad lights and shorted panel has similar symptom, if you disconnect ribbons from the panel and have sound + backlight always working then a bad diode or cap on panel's boards.

[peterkos2]

Re: Samsung UE 50 RU7092 restart

Good day. Thank you very much for your answers. We have located 4 pieces of resistors overheating, everything looks OK. I soldered the resistors out, measured OK. I soldered back, the picture jumped up and after a while it starts to shake at the bottom. So I soldered out one 59A resistor and the TV got a nice picture. It worked normally, but this morning I turned on the TV and after a while it fell into restarts. I can't measure 6514A parts. Can you advise me how? Are they diodes? How to measure? Thank you for your interest and time

[Davi.p]

Re: Samsung UE 50 RU7092 restart

you did not tell where are the resistors, and if the image shakes vertically, get a photo of resistors and where them are..

[peterkos2]

Re: Samsung UE 50 RU7092 restart

Foto
I soldered the circles out and the red ones back and the green ones not

[Davi.p]

Re: Samsung UE 50 RU7092 restart

ok now more clear, from the many threads here on badcaps on various models, also Sony but with Samsung panel, the main culprits are those or one of those diode packs D001/2/3/4, them are overvoltage protections that are to be removed to see if situation improves, first test them all in diode mode, only if you find a leakage you'll remove it, those are connected in some way to those resistors you've felt hot, if i under stand diode packs have one common anode (central pins) at gnd or connected to resistors, the other ones cathodes ( connected to gate drivers clocks), them are tvs diodes, hard to find in those format, but are to be replaced after all.

[peterkos2]

Re: Samsung UE 50 RU7092 restart

Thanks, I just don't know how to measure the diode test-10pin
I don't have a better datasheet

[Davi.p]

Re: Samsung UE 50 RU7092 restart

good! Is better than nothing... If i remember opposite zener are used in fact for overvoltage suppression, if you put multimeter in diode mode, between pins 1,2,4,5,6,7,9,10 and 3,8 must read open both ways..

[peterkos2]

Re: Samsung UE 50 RU7092 restart

So the error is there and cannot be corrected
Thank you all, at least I'm a little smarter
But the question is, it didn't actually start somewhere in the glass

[Davi.p]

Re: Samsung UE 50 RU7092 restart

The damage came from the electrical supply much probably.. destroyed the chip within the glass

[tiki66]

Re: Samsung UE 50 RU7092 restart

Looks like liquid damage to me, how did you clean LCD?

[peterkos2]

Re: Samsung UE 50 RU7092 restart

I don't know, I solved it for a friend