Plasma Pixelization SAMSUNG PS50B430

[creatou]

Hello everyone
I would like the opinion of plasma experts. Attached is the picture of a Samsung PS50B430 50 "Plasma TV during test pattern in service mode. The image is polished by pixels that sparkle mostly on the green and blue.
My voltages VS, Va, Ve, Vscan, Vcc, Vdd are correct.
I unplugged the LVDS from the logic main board and switched it to test mode (shunt pin 3 and 4). The black snow is always present on all the pattern of test. I can eliminate the hand board is already that

Do you have any idea of the cause of this defect.

Thank you for your help. Sorry for my poor Englis I am just French

[dick_barton]

Re: Plasma Pixelization SAMSUNG PS50B430

I would start by checking for poor solder joints on the board especially the X main.
Any pictures of your boards?

[ReeceyBurger123]

Re: Plasma Pixelization SAMSUNG PS50B430

Xmain failure DO NOT RUN THE SET IT WILL KILL THE YMain, remove the xmain and its thermal pads and resdoler eveything mounted on a heatsink.

[dick_barton]

Re: Plasma Pixelization SAMSUNG PS50B430

Good advice.

[creatou]

Re: Plasma Pixelization SAMSUNG PS50B430

hi,
Thank's for your reply.
I checked the welding on Xmain especially on the large inductors but nothing abnormal.
I'll check again this evening.

[dick_barton]

Re: Plasma Pixelization SAMSUNG PS50B430

A sharp clear picture of the underside would be more useful
Does that board clip into another board which connects to the X drive ribbons?

[creatou]

Re: Plasma Pixelization SAMSUNG PS50B430

I make a picture as soon as possible. The picture was just to show the Xsus card model

[ReeceyBurger123]

Re: Plasma Pixelization SAMSUNG PS50B430

Thats a different Xmain thats used in this model ? Ive had a different Xmain on this model fail loads and it always kills the Ymain as they use chained Erc.

[creatou]

Re: Plasma Pixelization SAMSUNG PS50B430

Can you confirm the position of the boad on the attached image for my unit.
1: Ysus
2: Zsus
3: Xlogic driver
4: Logic board
5: main boaord
6: PSU
Which board appears to be in default?
ReeceyBurger123 said "Xmain"

[ReeceyBurger123]

Re: Plasma Pixelization SAMSUNG PS50B430

Ahh right it is just a newer revision of the set. What is your Ve running at ?

[creatou]

Re: Plasma Pixelization SAMSUNG PS50B430

VE is 89V
Can you said me witch is the number of the board you name Xmain (see picture )
Thank's

[dick_barton]

Re: Plasma Pixelization SAMSUNG PS50B430

Board number 2 is the one I meant.

[creatou]

Re: Plasma Pixelization SAMSUNG PS50B430

Here is the Xmain board solder side in two part. I have reflow all the joint and test ! no change idem with the Ymain.

[ReeceyBurger123]

Re: Plasma Pixelization SAMSUNG PS50B430

I can see a few I dont like the look of reflow everything mounted on a heatsink as ve is good could be an Erc fault.

[creatou]

Re: Plasma Pixelization SAMSUNG PS50B430

As I said I remade all the welds. the photo are before! Ve is OK. What is ERC default
Many thanks for your help

[creatou]

Re: Plasma Pixelization SAMSUNG PS50B430

Yes ERC for the energy recovery circuit!
Do you think the panel may be faulty? Because a trace remains very quickly if I consult the menu for example but the trace disappears after.

[ReeceyBurger123]

Re: Plasma Pixelization SAMSUNG PS50B430

What do you mean bud ? What is Vsc running at as well ? This does look more of a Xmain fault as nearer the Ysus the panel looks better but drops nearer the Xmain.

[creatou]

Re: Plasma Pixelization SAMSUNG PS50B430

Vsc is OK ! I have reflow all the joints on The Ysus.

[ReeceyBurger123]

Re: Plasma Pixelization SAMSUNG PS50B430

Hmm might be worth upping Vs and Ve etc the panel isnt being sustained properly but could just be wear on the screen. Could also be worth doing a firmware update.

[creatou]

Re: Plasma Pixelization SAMSUNG PS50B430

The software update was my first step the software is the latest version.
I attemp to up Vs but no change.