Samsung PN51E450 - bad panel or bad boards?

[ngth82]

Good morning Badcaps!

I have a PN51E450 that i picked up a few weeks ago. I am finally getting to it.

The boards look okay, but I see dark regions on the screen and what appears to be misfiring / non-firing pixels. The screen has a few scratches. It does not appear to be a break.

Vitals:
Model: Samsung PN51E450A1FXZA
Panel: 851AX-YD01 (Vs=201V, Va=58V, Vsc=-185V, Ve=80V)
Y-buffer: 51EH Y-BUFFER(2LAYER), PCB LJ41-10183A, PBA LJ92-01882A
XY-Main: 51EH_XY-MAIN, PCB LJ41-10181A, PBA LJ92-01880A
Logic: 51EH LOGIC MAIN; PCB LJ41-10184A, PBA LJ02-01883A
Main board: BN94-060398
Power: BN44-00509A / PSPF291501A
Xbuffer - 51EH X-BUFFER, PCB LJ41-10182A, PBA LJ92-01881A

The panel voltage appear to be spot on to the sticker values (Vs=201V, Va=58V, Vsc=-185V, Ve=80V).

Before too much time is invested, whats the community thought on this one? I see scratches on the screen, but i'm not entirely convinced it's broken glass. It really does look like an object scratched the screen

That aside, is this a pad panel, or a bad board issue?

Thanks as always!
-Thomas

[DXseekerMO]

Re: Samsung PN51E450 - bad panel or bad boards?

Have you checked the display voltages while in operation? You may have to wait a bit to get an answer to your question if you are not a pro electronics repair guy. I'm trying to learn but the tumbleweeds do tend to blow around in my posts and help has almost disappeared from all of them.

Hopefully freakaftr8 will jump in he's real good with Plasmas, nice guy and willing to help almost anyone from what I see.. He helped me out on several Sammy plasmas!

[ngth82]

Re: Samsung PN51E450 - bad panel or bad boards?

Have you checked the display voltages while in operation? You may have to wait a bit to get an answer to your question if you are not a pro electronics repair guy. I'm trying to learn but the tumbleweeds do tend to blow around in my posts and help has almost disappeared from all of them.

Hopefully freakaftr8 will jump in he's real good with Plasmas, nice guy and willing to help almost anyone from what I see.. He helped me out on several Sammy plasmas!

Yes, the Vs, Va, Vsc and the Ve voltage appear to be correct while the TV is on.

Vs=201V, Va=58V, Vsc=-185V, Ve=80V

-Thomas

[DXseekerMO]

Re: Samsung PN51E450 - bad panel or bad boards?

Hope help comes soon. I really prefer plasma tvs.

[ngth82]

Re: Samsung PN51E450 - bad panel or bad boards?

Hope help comes soon. I really prefer plasma tvs.

This isn't my first rodeo...but yes, plasmas are nice for the color range. They dissipate more power and heat up the room in the summer time. But they are great tvs. I generally pick up LCD displays instead since there is less that can go wrong with them and repairs are cheaper.

I just generally shy away from picking up plasma units unless the original owner has a fairly good description of what happened to it. This one, the owner said it was a dim image, but i picked it up late in the evening and didn't notice the scratch on the screen. It was free, and it was on my way home. So no big loss if the panel is really toast.

[DXseekerMO]

Re: Samsung PN51E450 - bad panel or bad boards?

About two thirds of the 20-some TV's I've gotten were free. Always the best kind to get really. I have way more LCD's/LED's than Plasmas. I've always wanted to learn how to troubleshoot and fix them so I decided to just go ahead and do it.

[ngth82]

Re: Samsung PN51E450 - bad panel or bad boards?

Just checking in.. does anyone have a suggestion going forward? Is this even worth an attempt to fix by replacing the xy-main, ybuff or the x-buffer?

[dick_barton]

Re: Samsung PN51E450 - bad panel or bad boards?

Here's the fast track guide. Sorry can't really help as plasma's are not my area of interest.

[freakaftr8]

Re: Samsung PN51E450 - bad panel or bad boards?

Looks like a y sustain problem in the -vy section. Seen it before. A new y sustain will probably cure the issue. Check all resistors especially the green power resistors on the board.

It would not hurt to go through the power supply and brush up on soldering of all Transformers and mosfets connected to the aluminum heat syncs.

[ngth82]

Re: Samsung PN51E450 - bad panel or bad boards?

Thanks for the suggestions.

I guess the next step is to give everything a second check. The initial inspection looked "OK" for voltages and visually was fine.

I'll check the power resistors again and touch up all the locations on the Y-sus. I'll update you all this weekend.

Happy Friday!

[ngth82]

Re: Samsung PN51E450 - bad panel or bad boards?

Thread closed.
I ended up giving the TV away. Replacement boards were a bit higher than what i wanted to spend on the TV repair. I hung on to this TV for close to 2 months. It was time for it to go!

I touched up all the connections on the X-y_main board and double checked the voltages. No change.

Onwards to the next unit! I picked up a Insigna 32" LED unit circa 2013... it has four bad backlight LEDs that i'm replacing later today.

Thanks for the advice all.