Samsung Plasma HP-T5054 Sound but no video

[kevinm34232]

Re: Samsung Plasma HP-T5054 Sound but no video

Tom I got a replacement main board today and it didn't fix it. Of course I cannot be 100% sure the replacement board is working but do you think it's the control board then?

[tom66]

Re: Samsung Plasma HP-T5054 Sound but no video

I'd say it is unlikely, it's possible but without a scope to check LVDS waveforms you can't rule out the control board.

[kevinm34232]

Re: Samsung Plasma HP-T5054 Sound but no video

OK guys got the new logic control board today and that was the problem... Put the old main board in and it also worked... Murphy's Law. Thanks Tom for narrowing it down so quickly.. You think it's that main processor on the control board with the heat sink that failed?

[tom66]

Re: Samsung Plasma HP-T5054 Sound but no video

Probably that processor. They also have firmware on them, which can be corrupted by a bad software update, although I can't see how it would still do test patterns... Murphy does like to mess your around!

[nwcs]

Re: Samsung Plasma HP-T5054 Sound but no video

I have no video and good sound. I did some testing and I have no VS at all, VA is 63v. I checked the vs and va with cn807 thru cn810 plugged in and unplugged no difference. Customer just had the power supply rebuilt so I have to wonder if something may have killed the repair. I did check both buffer boards and they test ok. The y main has two open fuses F5700 and F5200 as well as what looks like a leaky cap but does not test bad.. I am really just learning how to repair plasma's and if I understand correctly this means the smps is bad but since there are two open fuses on the y main it must be bad too. Any help would be greatly appreciated.

[tvtimmy]

Re: Samsung Plasma HP-T5054 Sound but no video

The gunk between the blue caps is just glue.

[nwcs]

Re: Samsung Plasma HP-T5054 Sound but no video

I was not looking at the glue but what looks like the dielectric oxide from under the cap that ran down the board.

[ReeceyBurger123]

Re: Samsung Plasma HP-T5054 Sound but no video

Ive seen that same stain on them before not the caps just some sort of silicon samsung use also. Not much info at all, is Vs dead short on Ymain or Xmain ? If no then Psu is faulty still. Also I suggest you also tighten all screws on Ysus heatsinks and replace ALL samwha Pt 680uf 25v caps on Ymain and Xmain as well as heat sinking the buffer Ics.