Samsung PN50A450 No picture issue.

[topfli8979]

Have a Samsung Pn50A450 plasma tv, picked it up clicking off and on. Diagnosed ymain had 3 faulty fets on heat sink. Purchased remanufactured ymain, now the tv stayson,no clicking, y main is humming like it should, panel has light glow. But I still have no picture,menu,nothing on the display.

[tom66]

Re: Samsung PN50A450 No picture issue.

OK, if you post a pic of the control board (connects to y-main through flat flex cable) I will outline procedure for making it show test patterns to prove plasma boards work. Main board is common failure on this model.

[topfli8979]

Re: Samsung PN50A450 No picture issue.

I know,sorry for picture quality.

[tom66]

Re: Samsung PN50A450 No picture issue.

Mkay, see image.
All connection changes done with power OFF and set UNPLUGGED.

When you power up with the jumper in place you should see test patterns:
http://www.youtube.com/watch?v=JCtF53GKE0A

[SumDarkPlace]

Re: Samsung PN50A450 No picture issue.

I have a similar model, PS-50A457P1D, with the same fault. Replaced bad caps on power supply and Y-sus, and now screen lights up, but no picture, just sound. Mine has the same control board as above, but jumping 3 &4 doesn't produce test images. I'm guessing a mainboard is my next replacement?

[tom66]

Re: Samsung PN50A450 No picture issue.

If the test patterns don't work but the screen is definitely glowing, it's more likely the control board is at fault (the one in the picture above.) Make sure LVDS is definitely disconnected.

[SumDarkPlace]

Re: Samsung PN50A450 No picture issue.

Thanks, I'll grab a control board, and give it a go

[topfli8979]

Re: Samsung PN50A450 No picture issue.

Yea the jumper across 3 and 4, with lvds cable disconnected does no show any patterns,colors etc. The control has 2 leds on it, one is blinking the other briefly lights when powered up then goes off. I guess I will be looking for a control board also.

[topfli8979]

Re: Samsung PN50A450 No picture issue.

Replacing the control board, did not fix the issue, still cannot get test pattern to come up. So i guess im looking for a new main.

[tom66]

Re: Samsung PN50A450 No picture issue.

Main what? X-main, Y-main, main board?

[topfli8979]

Re: Samsung PN50A450 No picture issue.

main board

[topfli8979]

Re: Samsung PN50A450 No picture issue.

tom do you have the service manual for this model?

[tom66]

Re: Samsung PN50A450 No picture issue.

Not gonna be the main board. The test you did basically has isolated the main board. It's PSU, x-main, y-main, buffers or panel now.

http://www.tgohome.com/ServiceManual...&Search=Submit

[topfli8979]

Re: Samsung PN50A450 No picture issue.

Really? Y main with buffers built in is new, psu voltages are good. X main heat sinks are warm like should be. Panel has glow.

[tom66]

Re: Samsung PN50A450 No picture issue.

Panel has glow, but when you do the 3-4 test, is it still glowing?

[topfli8979]

Re: Samsung PN50A450 No picture issue.

Glow is there either way, only difference is with jumper connected it right when screen first powers up "GLOWS" it has different colored sparkles everywhere for a half second. It just a black glowing screen with lvds cable connected and no jumper.

[tom66]

Re: Samsung PN50A450 No picture issue.

Did you disconnect LVDS during the jumper? Sounds like Y-main fault.

[topfli8979]

Re: Samsung PN50A450 No picture issue.

Yes lvds disconnected during jumper, this is second y main I have tried, first board I purchased was thought to be defective so I returned it, new one same thing.

[tom66]

Re: Samsung PN50A450 No picture issue.

Don't know then, unfortunately.

[topfli8979]

Re: Samsung PN50A450 No picture issue.

Im not gonna give up on this beast. I unplugged the x main, screen gets a red tint. Only other board possibility is psu or main.