Samsung Plasma PN51D490 No picture.

[jeffegg2]

At first only sound, then after two power ups, just the red light blinks 6 times.

No swollen caps... :-(
Unplugged X and Y, still just green blinking light. 34 jumper no change.

Checking voltage at Va and Vs. When I turn it on, the voltage goes to the setting, then starts dropping right away.... I'll have to continue checks on the ps board..... Kinda brown by the thermistors, but they seem to be working.

any tips?

Thanks! Great site!!

[ReeceyBurger123]

Re: Samsung Plasma PN51D490 No picture.

Could you take pictures of all the boards please, make sure they are well focused and of the whole board.

[jeffegg2]

Re: Samsung Plasma PN51D490 No picture.

[jeffegg2]

Re: Samsung Plasma PN51D490 No picture.

[tom66]

Re: Samsung Plasma PN51D490 No picture.

We really need higher resolution photos, as close to the max (3000x3000) as possible.

[jeffegg2]

Re: Samsung Plasma PN51D490 No picture.

[jeffegg2]

Re: Samsung Plasma PN51D490 No picture.

https://<iframe src="https://www.fli...reen></iframe>

[jeffegg2]

Re: Samsung Plasma PN51D490 No picture.

https://flic.kr/p/rbJ92T

[jeffegg2]

Re: Samsung Plasma PN51D490 No picture.



https://<a href="https://www.flickr....5JP_7126"></a>

[ReeceyBurger123]

Re: Samsung Plasma PN51D490 No picture.

Its not loading you can upload pictures, through the advance feature.

[jeffegg2]

Re: Samsung Plasma PN51D490 No picture.

I'll try, how to delete a posting???

[jeffegg2]

Re: Samsung Plasma PN51D490 No picture.

Ok, so i'm checking the y board, and found what appears to be a shorted power mosfet. the third led de-soldered easy. the first and second have what looks like little bumps around it and refuses to unsolder.... do I have to drill this out or what? Haven't done any serious solder work since the 80's..... this does not look like a normal thru hole to me.

thanks....Jeff.

[tom66]

Re: Samsung Plasma PN51D490 No picture.

What soldering iron do you have? Those are solder rivets, they are used to provide more rigid support. They should just desolder normally.

[jeffegg2]

Re: Samsung Plasma PN51D490 No picture.

Perhaps my iron is set too low for that one... I did get it. Actually destroyed the power mosfet getting it out. eh. well found the culprit on the Y board. Some kind of diode shorted. I still have to check out the x board....

[jeffegg2]

Re: Samsung Plasma PN51D490 No picture.

right part, wrong part of the board. sorry. it was in D5010.

[jeffegg2]

Re: Samsung Plasma PN51D490 No picture.

how does one go about getting the service manual? is it even necessary?

Thanks for all your help...

[jeffegg2]

Re: Samsung Plasma PN51D490 No picture.

found two more shorted on the Y board. X board checks out ok...

two RJP30H1 fast switching IGBT. Q5002 and Q5017.
one SF10A400H diode. D5010

thanks for all the help here. I'm on my way to electronics repair station... heh.

[tom66]

Re: Samsung Plasma PN51D490 No picture.

Unfortunately, there won't be any schematics for the board.
Can you highlight where the failed IGBT was, does it have some lettering like "Ys", "Yg", "Yr", "Yf", etc. next to it?

[jeffegg2]

Re: Samsung Plasma PN51D490 No picture.

YS and YG.

What should I do about all the silicone? that I removed? hot melt? or fresh silicone?

Thanks.

[tom66]

Re: Samsung Plasma PN51D490 No picture.

Since Ys and Yg are bad, I'd recommend replacing the little driver ICs that control them, can you post a picture of underneath those devices, solder side?

Silicone, that's only there for mechanical support so some back in if you feel it to be necessary. Hot glue works ok.