Samsung PS51E450 screen issue

[notallbad]

Whats the general thoughts on this one?

Plasma panel!

[notallbad]

Re: Samsung PS51E450 screen issue

Va 58v
Vsc -180v
Vs 207v
Ve not getting 78v, jumping around 200,400,600 etc...

[notallbad]

Re: Samsung PS51E450 screen issue

Should I adjust Vs down as its reading slightly high?

Strange, it is reading 201v now!

[dick_barton]

Re: Samsung PS51E450 screen issue

One area looks like it's been getting really hot. I would check the components on the underside and all the solder joints in that area.

Have you tried running just the test pattern check.

[notallbad]

Re: Samsung PS51E450 screen issue

How do I get the test pattern check on?

Yh, I did notice the scorch mark, will check it our.

[dick_barton]

Re: Samsung PS51E450 screen issue

Do a search on this forum to get the right info.
For many sets it's disconnect the mainboard ribbon to the logic board and jumper the Auto-Gen pins on the logic board then power up.

[notallbad]

Re: Samsung PS51E450 screen issue

On reverse of scorch mark is a SMK630 N-ch power mosfet.

[notallbad]

Re: Samsung PS51E450 screen issue

can't find test pattern jumper on logic board

[dick_barton]

Re: Samsung PS51E450 screen issue

It seems to suggest that it's 1 & 2 shorted together and also 3 & 4 shorted together for PAL but I'm not 100% sure.

[notallbad]

Re: Samsung PS51E450 screen issue

well, won't know unless someone tries it, so here goes.

So put the jumpers across and with the main (cn2023) ribbon cable disconnected power up, yes?

[notallbad]

Re: Samsung PS51E450 screen issue

Well, just a black screen with the sparkles (discharge) still.

But what I do notice now is 2 thin blue lines down the middle of the screen. Not looking good.

With the jumpers back off and main disconnected its just a black screen. Just for info.

[dick_barton]

Re: Samsung PS51E450 screen issue

Try with just 1 & 2 shorted and CN2024 (if that goes to mainboard ) disconnected.

Edit
Is Ve back to 78V . If not this would need to be resolved. Previous posts on this model suggests a plasma screen fault, but you never know.

[notallbad]

Re: Samsung PS51E450 screen issue

Yh, that done it.

1 and 2 jumpered and main disconnected.

Screen white. blue. red, green etc ..

Would agree now, screen damage!

I believe this was caused by liquid damage, attempt to clean the screen possibly.

VE still jumping around like crazy!

[tvtimmy]

Re: Samsung PS51E450 screen issue

Screen is bad.

[notallbad]

Re: Samsung PS51E450 screen issue

Yh, quite sure too so just gonna strip it down for spare components from the boards.