Samsung PN43E450 Panel flashes no video VS VA drop

[JayRolla]

Trying to fix this PN43E450 plasma. When you plug it in you get the samsung chime, plasma shows a flash of a few pixels and then nothing, tried all inputs dont get sound.

I believe panel is good since it flashes. I get good standby power, when hitting power button nothing happens, dont turn off or shut off, PS_On voltage never changes, have to pull power to get unit to shut off and then it chimes when powering up.

When it chimes and the panel flashes the VS and VA are good and then it slowly drops off, ive tested by unplugging boards left and right and I never get voltage too hold.

Voltage still dropps with control board disconnected but when I hit the power button I dont get any PS_ON voltage, thinking bad mainboard?

Thanks ahead of time for the help.

[tom66]

Re: Samsung PN43E450 Panel flashes no video VS VA drop

Blimey! E series PDP already dying?! Less than 2 years old!

Try 3-4 jumper trick:
https://www.badcaps.net/forum/showpo...61&postcount=2

Should debug where problem is.

Note: Control board will shut down if either Y-main or X-main are disconnected on these models, making isolation of the problem tricky.

[JayRolla]

Re: Samsung PN43E450 Panel flashes no video VS VA drop

Blimey! E series PDP already dying?! Less than 2 years old!

Try 3-4 jumper trick:
https://www.badcaps.net/forum/showpo...61&postcount=2

Should debug where problem is.

Note: Control board will shut down if either Y-main or X-main are disconnected on these models, making isolation of the problem tricky.

Yea its making me crazy this thing is already failing, its not mine but still, I will never buy another Samsung, loved them so much years ago. I will do the test.

[hienton2]

Re: Samsung PN43E450 Panel flashes no video VS VA drop

There may be some shorts in y main or x main . Check y main first.

Is led on logic board blink?

[whiz62]

Re: Samsung PN43E450 Panel flashes no video VS VA drop

JayRolla, Did u ever figure it out? Got same
problem.

[tom66]

Re: Samsung PN43E450 Panel flashes no video VS VA drop

Check panel VERY carefully for cracks. Will cause this exact symptom.

[whiz62]

Re: Samsung PN43E450 Panel flashes no video VS VA drop

I looked it over pretty good with light and glasses on and cannot see any cracks. It looks like someone has worked on Y board by markings on heat sink. I have posted my own thread with pics and voltages earlier. Guess I gotta dig deeper.

[whiz62]

Re: Samsung PN43E450 Panel flashes no video VS VA drop

installed y main,y buffer and x main and It fired up with a lot of black lines, see pics. Ran it for awhile just to see what would happen and almost all lines gone but now have a purple haze and some solarization going on.

Just hoping someone has seen this before and it is not the screen.

[tom66]

Re: Samsung PN43E450 Panel flashes no video VS VA drop

Check X-main. Make sure all cables seated fully. If you have a scope, now would be the time to check the X-main output waveform. Also check Ve.

It's an odd fault. The purple tint is classic X-main fault, but the horizontal lines have me a little worried. The fact that they go away though is a good sign generally.

[Alastair E]

Re: Samsung PN43E450 Panel flashes no video VS VA drop

Summit going on with the X-Main, Have you a scope?

Those remaining black lines are probably the tabs need reseating in the plugs of buffer-board--they can be a pain to get right in as some have small lugs on the sides that need to locate in slots....

[whiz62]

Re: Samsung PN43E450 Panel flashes no video VS VA drop

Thanks guys for the quick replies. I don't have a scope but will recheck all cables and such and report back.

[whiz62]

Re: Samsung PN43E450 Panel flashes no video VS VA drop

Checked y buffer board ribbons and all lines are gone. checked ve and it is 94vdc. Checked all connections at x main. would it hurt to try old x main and see how display acts or will it blow the y components? here is pic as of now. still has that purple haze which makes picture darker.

[whiz62]

Re: Samsung PN43E450 Panel flashes no video VS VA drop

Anyone know what the Ve voltage should be? I am getting 94v.

[tom66]

Re: Samsung PN43E450 Panel flashes no video VS VA drop

Sounds about right.

[whiz62]

Re: Samsung PN43E450 Panel flashes no video VS VA drop

Success! I worked and checked, rechecked, studied these last few days and finally decided after reading tom66's thread on plasma repair to try my original X main and bam, perfect picture! Thanks tom66 and Alastair E. So Shopjimmy can make mistakes too.