Samsung PS58B685 (like pn58b650). Sound but no image.

[Wrecked]

Hello all

I could really use some help with this Samsung Plasma TV.
It has been running fine for 6 years until a few days ago. Then the picture just disappeared. Screen went totally black, and the usual loud hum was gone. Audio still worked though.

I took it apart and started debugging. Power supply board seems to deliver the voltages written on the connectors, and the logic board blinks every second. All caps looks fine! I then looked at the X and Y-mains.

I found 2 pico fuses that was blown. One on Y-main, and one on X-main. I have attached pictures with arrows pointing at them.

Then I measurred the Y-buffer, but no short was found. (not 100% sure I did it right, just saw a video on youtube about it)

I did replace the 2 fuses with some of same spec (1A, 125V), and when I powered it on, sparks was flying, so I turned it off at once.

The sparks came from 2 components looking like FET's on the Y-main board.
Both the fuses I replaced were still OK.

I have attached a picture of the burned FET's.

Im not sure what my next step is now, and would like your advise.

What baffles me, is that I found a blown fuse on both X and Y main. Otherwise, I would just replace Y-main and buffer boards.

Anyone able to help me on this one?

(I have meassuring equipment, and access to a scope if nessesary)

Thanks in advance!

Jimmy

[Wrecked]

Re: Samsung PS58B685 (like pn58b650). Sound but no image.

Pictures:

[ReeceyBurger123]

Re: Samsung PS58B685 (like pn58b650). Sound but no image.

Hmm shorted fets on the Ymain and Xmain this set chains the erc meaning Y can kill X. You should replace the Ymain and Xmain or you could possibly go about repairing them which we could help with but it will be an involved process and there could be some explosions before it works. Up to you ?

[Wrecked]

Re: Samsung PS58B685 (like pn58b650). Sound but no image.

Thanks for your anwser!

I just bought a set of used X and Y mains on eBay. Are there anything else I should check or replace while Im at it?

I guess I could double check the Y buffer boards for shorts, and also check for shorts between + and - of the input. But besides that?

[Wrecked]

Re: Samsung PS58B685 (like pn58b650). Sound but no image.

Update:

Got my used Y-main and on X-main from eBay this week, and just got around to try them.

I meassured the Y-buffer again for shorts, but found nothing wrong, so I crossed my fingers and fired it up. The picture is back and everything seems fine, and as a nice bonus the loud hum is gone :-)

Thanks for helping out!

[ReeceyBurger123]

Re: Samsung PS58B685 (like pn58b650). Sound but no image.

Awesome