Samsung plasma TV PS-42V4S repair

[PowerAmpFreak]

Hi all. New to this forum. A short presentation...
I'm working professional with electronics repair and development. I'm mostly involved with switchmode powersupplies and audio power amplifiers.
I'm sure I can assist some people in questions in this field.
From time to time I'm involved in TV-service aswell. This time my own dear Samsung plasma screen, model PS-42V4S, need some help.
I will try to explain the problem:

The entire screen has vertical lines from top of the screen, all the way to the bottom which is not lit (one pixel wide). In each inch of the screen there are 4-5 lines which is off. The pattern repeats itself through the entire screen.
BUT, the menu and all OSD information is displayed correctly, which means all the final output and multiplexing is working correctly, otherwise also the menu and osd would have these vertical lines. Also, the smps must be ok.
In other words, all these dark vertical lines is lit ok through the menu/osd.

Unfortunately, this could indicate a problem with the video scaler or other video processing circuit on the logic board. There are two processors which is named "ASI501" which is a BGA, in other words very hard to replace. The other is a FL12310 which is possible to replace.

I may start with this and I hope I managed to explain the problem good enough.

Thanks.

Regards
PowerAmpFreak

[Wizard]

Re: Samsung plasma TV PS-42V4S repair

Replace logic board itself failed because one address line lost (repeated lines) for the Z-drive (the boards at bottom are all bus paralleling all the drive ICs bonded to the panel itself). The small board sitting on the panel itself with 4 screws. This is one with many ribbons out to other boards and twisted pairs LVDS cable to the main board.

You need panel part number to reference to the logic board. I can supply you with part number.

Need full model number and version #. This is on small sticker on back panel usually on left near edge.

Cheers, Wizard

[PowerAmpFreak]

Re: Samsung plasma TV PS-42V4S repair

First of all, thank you for responding, Wizard.
I was afraid my attempt to describe the problem, was not good enough.
So, one adress line is missing for the final multiplexing chippery?
This is what I found on the logic board itself:

Board: NELSON
Code: BN41-00452 C
Rev: MP 1.4 (2004-08-19)

I just want to say again, that MENU and OSD information is completely ok. All missing lines is OK in the menu and osd field. Could it still be loss of one adress line then?
Is it possible to measure the adress line and check for activity, to determine which IC is bad?

Regards
PowerAmpFreak

[Wizard]

Re: Samsung plasma TV PS-42V4S repair

Please supply full model and version # on the small sticker on right side on back usually. I asked this already. The part number on the board is not the correct part #.

Cheers, Wizard

[PowerAmpFreak]

Re: Samsung plasma TV PS-42V4S repair

Hello Wiz,
Here's the modell number:
Samsung PDP module modell S42SD-YB03
Manufactured 2004.08.21

Hope this is the information you need, thanks a lot!

Best regards
PowerAmpFreak

[Wizard]

Re: Samsung plasma TV PS-42V4S repair

That's panel model. Samsung applies part numbers to everything, I need the two items of info so I can look up in service manual for correct part number.

I'll ask again, I need Model # (in full) and version number (3 to 4 characters).

Full model is like this for your for example:

Model code: PS42V4SX/XAC
version: SD01

Please vertify.

Cheers, Wizard

[PowerAmpFreak]

Re: Samsung plasma TV PS-42V4S repair

Oh sorry ... I'll provide you with the correct information tomorrow when I see the TV again, thanks (Slap me sideways with a big fish )

[Wizard]

Re: Samsung plasma TV PS-42V4S repair

Aw that's funny. Don't be so self-shamed.

Cheers, Wizard

[PowerAmpFreak]

Re: Samsung plasma TV PS-42V4S repair

The only model code I can find is on the back panel, where it says:

Model: PS-42V4S
Type: NS-42V4

There are no other sticker anywhere inside or outside.
I can't find anything like version number or similair.
I've some photos of the screen, showing the problem, if you like.

[Wizard]

Re: Samsung plasma TV PS-42V4S repair

Photos please thank you. Won't have part number till I get back to work this monday and I'll look up. In mean time produce the photos for anyone to see.

Cheers, Wizard

[PowerAmpFreak]

Re: Samsung plasma TV PS-42V4S repair

I try to include two attachments with photos of the screen. It's possible to see the vertical lines in the picture, while the menu and osd graphics is not having the problem. This must mean that all screen drive electronics is ok.
The other picture shows that all lines is ok during "blue screen" when no video source is connected.
So, why does the video picture have the vertical lines problem, and the menu graphics does not?

Regards
PowerAmpFreak

[Wizard]

Re: Samsung plasma TV PS-42V4S repair

You just diagnosed it.

Panel itself is fine, and parts of the mainboard functions. But other parts on the same mainboard failed. Replace the mainboard. Not the logic board.

Menu/text is fed from different chipset via different source to the main chipset that handles the LVDS output to the logic board is functional but other signal that is feeding to that chipset from analog to digital converter failed. Have you tested with HDMI input?

Cheers, Wizard

[PowerAmpFreak]

Re: Samsung plasma TV PS-42V4S repair

Wizard, is this the main board? (check attachment)
I actually spoke with a local Samsung repair department, and they told me no parts are available anymore. But, I can buy some of the IC's and change.
I'll have a look in our microscope at work to check for soldering problems with big IC's or bus resistors.
Maybe you know which IC's handle the video signal and could possibly give such a problem? I didn't check with HDMI, since I've no such source.

[tmwalsh]

Re: Samsung plasma TV PS-42V4S repair

Have you tried composite input(yellow), component(3 RCA cables Green Blue Red) input or S-video? Almost every low priced DVD player would have those available. That would check several paths through the innards.
tom

[PowerAmpFreak]

Re: Samsung plasma TV PS-42V4S repair

Yes, both scarts and composite input is tested - same result. Not tried SVHS, component or HDMI. I doubt this will make a difference, since I suspect the problem is upstream in the picture processing chippery.

[Wizard]

Re: Samsung plasma TV PS-42V4S repair

Hard to say. Best to replace whole mainboard. Try to get one used. Otherwise new LCD TV.

Cheers, Wizard

[PowerAmpFreak]

Re: Samsung plasma TV PS-42V4S repair

Wiz, is it possible that you will run into a suitable board that I could buy?

[Wizard]

Re: Samsung plasma TV PS-42V4S repair

Like I said I need the full model code. it has 3 to 4 letters on the end of the model.

Ill try.

Is yours PS42D4SMX/BWT?

Also the mainboard, are these separate boards? (analog and digital) Need another photo of whole area of the mainboard where mainboard pan is.

See, you are giving me bit difficult time because of little details left out.

Cheers, Wizard

[PowerAmpFreak]

Re: Samsung plasma TV PS-42V4S repair

Wiz, not my intention to give you headache...
I wasn't able to find any sticker with full model number. Maybe it's under a pcb, or something. I will see the TV this wednesday and will update accordingly with new pictures covering the entire set and mainboard in full.
I really appreciate your help, Wiz!

[Wizard]

Re: Samsung plasma TV PS-42V4S repair

full model is on the back panel with the serial number.

Cheers, Wizard