Sammy Plasma pn50c7000yf won't stay on after lightning storm

[ranergeo]

Hi! I have a Samsung PN50C7000YF I've acquired that won't stay on. The owner told me that it was working great 'till lightning struck his shed in the back yard. The hit only took out the modem and the TV. I figure a great deal (free) on a 3D tv is hard to pass up, so I thought I would take a stab at it, but can't find a service manual online to work with!

This is what it does currently: The minute I plug it in, with no remote or power input, it will attempt to turn on... I hear the click from the PCB, only to be followed by another click (also from the PCB), and a brief white flash on the screen before it turns off and repeats the process. Other posts have often pointed to a surge running through an HDMI, LAN, or cable input into the Main, and would like to somehow separate out the main from the rest of the system.

Simply unplugging the Main from the PCB keeps it from turning on, so I'm not sure if I can do some tests that way as well. Any help would be appreciated before simply shotgunning pats at it! Thanks

p.s. I've posted some pics of what I'm looking at... let me know if you need more.

[tom66]

Re: Sammy Plasma pn50c7000yf won't stay on after lightning storm

Nice for free!!
This is probably a main board fault.

In a dark room do you see a glow from the plasma panel after the first flash and before it shuts off?

Can you remove this metal bracket:
https://www.badcaps.net/forum/attach...6&d=1386360381

and get a picture of the board underneath it.

[ranergeo]

Re: Sammy Plasma pn50c7000yf won't stay on after lightning storm

Yeah! His homeowners paid for a new (larger) one, so he had no reason to keep the second and fix it!.. score!

The screen flashes like its firing, right before it turns off... it doesn't necessarily "glow".

I've attached the pic of what's under the bracket, hope it helps!

[tom66]

Re: Sammy Plasma pn50c7000yf won't stay on after lightning storm

OK, see the following post:-
https://www.badcaps.net/forum/showpo...61&postcount=2

On the control board your 2x2 header is CN2010 and the orange cable is the LVDS.

After doing this you may or may not see test patterns on the plasma panel.
If you see test patterns: main board bad (HDMI board)
If you do not see test patterns: check LED on control board - if it blinks 5 secs, pauses 2 you have a Y-buffer, Y-main or X-main failure.

[ranergeo]

Re: Sammy Plasma pn50c7000yf won't stay on after lightning storm

O.K., did the tests as prescribed and got none of the options. The power supply made the usual "click" to turn on, and just as it seemed as if the screen would want to light up, the PCB clicked again (from a different location) and turned off. It would continue to repeat this 'till I unplugged it.

On the control board itself, after the first click, one green LED would turn on, and a second later, one next to it would turn on, which was the same moment the set turned off. Not sure if that is helpful or not.


btw - Although I said I was going to try to prevent shotgunning parts at it, I found a main board on e-bay for $32 (with a return policy), and figured it couldn't hurt. I'd still rather be a little more certain, tho!

[tom66]

Re: Sammy Plasma pn50c7000yf won't stay on after lightning storm

It may need the power supply jumpered because the main board might be shutting down. Can you see a list of pin labels (legend) next to the power supply connector on the connection going between the main board and power board?

[ranergeo]

Re: Sammy Plasma pn50c7000yf won't stay on after lightning storm

Sorry for the delay... yes, there is a little legend box right above the connector. From top to bottom it is labeled:

15v - PS on
15v - stby
5.3v - 5.3v
5.3 - rtn
rtn - rtn
rtn - rtn
15v - rtn
15v - n.c.
15v - n.c.

[tom66]

Re: Sammy Plasma pn50c7000yf won't stay on after lightning storm

There is not a pin marked VS ON?

[ranergeo]

Re: Sammy Plasma pn50c7000yf won't stay on after lightning storm

No, just the one at the top saying 15v -p.s. on...
(I'll be back momentarily to continue this, but need to step out for a bit)

[tom66]

Re: Sammy Plasma pn50c7000yf won't stay on after lightning storm

OK, when you get back, connect a wire from PS ON to GND. Leave the jumper in place on the control board and also keep the LVDS disconnected.

[ranergeo]

Re: Sammy Plasma pn50c7000yf won't stay on after lightning storm

Just to confirm, should I disconnect the cable from PCB to Main before running that jumper, or just add it in? Thanks!

[ranergeo]

Re: Sammy Plasma pn50c7000yf won't stay on after lightning storm

Oh, I did find the VS-ON pin, but it is on a cable going between the PCB and control board.