Samsung plasma TV PS-42V4S

Need to describe the problem better: There are a lot of vertical lines on the screen not lit at all. I would say 1st, 5th and 10th.. and it all repeats again. So most of the picture is there but is loosing some lines in every inch of the screen from left ro right.

Are you saying there must be no problem with the final demultiplexing chippery at the screen as the Menu/OSD display comes up fine?

In my world, thinking in terms of old CRT screens which recieve R,G,B signals to drive the tube, the menu OSD information is mixed together with the CVBS signal and fed the the RGB amps. If there was a faulty tube, giving for instance, no red colour, both picture and osd information was affected. In this plasma case, all "dark" lines starts to light when displaying osd information. That makes me believe the plasma screen itself and it's drive electronics is ok. I know very little about plasma technology, was mostly involved with crt tv repairs back then. Is my thinking incorrect? I would love if there were some faulty power electronics failure, instead of scaler/picture processing dsp failure. But of course I don't know yet. Appreciate any advice to move on. Thanks a lot!

Regards PAF

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I would suspect a lifted contact on a SMD lead somewhere back in the initial video processing

This is exactly the hints I need. Could you possibly explain it a bit further? May I contact you directly by mail?

Regards PAF

Can you read schematics? The service manual for that set appears to be available here:

This definitely sounds like a scalar problem; not a driver or panel issue. Many manufacturers use Samsung panels and drive electronics in their plasma sets. The actual video processing is handled on a single card designed and manufactured by the company whose name will appear on the finished product. I would not be optomistic of this being repairable at the component level. The video processing card consists of a number of fairly complex processors working together.

PlainBill

I'm familiar with schematics, I'm working my electronics, but not plasma TV's unfortunately.. I did buy the service manual for the TV, at nodevice.com. Thanks for the link! Unfortunately, the service manual wasn't complete, the smps part and output driver parts were missing, but it seems most of the video processing board is there. I suspect one of those processors to be the problem: ASI501 which isn't possible to desolder (legs are underneath) GENESIS FL12310 (possible to desolder) I guess one of these ic's is the scaler.

In case, anyone has a complete board for no use, I'm interested (not too optimistic...)

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

When having no input source connected, the screen is ALL blue. (all lines OK) Pressing MENU, it all looks briliant. Connecting a video source, the picture has the "vertical lines" problem. (still menu and all OSD is ok) Also, I noticed, when having no input source connected (blue screen) and apply input source, then screen goes all black for one second, before it displays the video. During this second, when screen is black, it's possible to see the veritcal lines problem very faint in the black screen aswell.

As Plainbill said, I'm also starting to loose my optimism in getting this nice set back to life.

I was calling local Samsung service, they absolutely have no spare parts for such an old set from 2004/2005. They even have problems to get spare parts to one year old sets... That's unbeliveable! How can they offer that bad customer service. All they want to is selling new sets appearently.

Regards PAF

I'm familiar with schematics, I'm working my electronics, but not plasma TV's unfortunately.. I did buy the service manual for the TV, at nodevice.com. Thanks for the link! Unfortunately, the service manual wasn't complete, the smps part and output driver parts were missing, but it seems most of the video processing board is there. I suspect one of those processors to be the problem: ASI501 which isn't possible to desolder (legs are underneath) GENESIS FL12310 (possible to desolder) I guess one of these ic's is the scaler.

In case, anyone has a complete board for no use, I'm interested (not too optimistic...)

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

When having no input source connected, the screen is ALL blue. (all lines OK) Pressing MENU, it all looks briliant. Connecting a video source, the picture has the "vertical lines" problem. (still menu and all OSD is ok) Also, I noticed, when having no input source connected (blue screen) and apply input source, then screen goes all black for one second, before it displays the video. During this second, when screen is black, it's possible to see the veritcal lines problem very faint in the black screen aswell.

As Plainbill said, I'm also starting to loose my optimism in getting this nice set back to life.

I was calling local Samsung service, they absolutely have no spare parts for such an old set from 2004/2005. They even have problems to get spare parts to one year old sets... That's unbeliveable! How can they offer that bad customer service. All they want to is selling new sets appearently.

Regards PAF

If you find a pressure sensitive BGA or similar IC, bits of rubber, wooden wedges and cable ties around the IC and through a known, maybe multilayer track-clear, section of pcb could give a bodge fix

oden

I did test to apply pressure to all of the ic's on the video processing board without any difference. I was out of freeze spray, maybe that could give some hints which ic is bad.. But. the failure shouldn't be in the smps / X-Y screen drivers or similair.. It's still most "hot" in the video processing parts?

A quick lecture on how plasma sets are built. Samsung has a division that produces plasma panels. These are wholesaled as a 'display unit' consisting of the panel, drivers, sustain boards, and a power suppy. The power supply is customized for the particular wholesale customer. The customer then adds a case, signal input card, audio amp, speakers, etc. This results in a TV where physically most of the parts are not under the manufacturer's control, and consequently schematics that don't cover the whole TV.

As an aside, I just repaired a Philips plasma set, based on a Samsung panel. The schematics are available, but only covered the parts supplied by Philips. Virtually all of the processing was handled on the Small Signal Board. The schematic for it ran to more than 12 pages.

I'm not familiar with Samsung's TVs, but the Philips schematics identify a part refered to as the 'scalar'. I would say that it is very likely that the problem is in that part.

Parts availability has been a problem at least since the building of the Pyramids. Imagine ordering a new stone from the quarry. PlainBill

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I found what I believe is the scaler IC (ASI501) as spare part, but I don't know who has the tools to change it. At my work, we have heat gun soldering tools and microscopes, so other IC's with 500 legs are possible to replace. But not BGA's... The service manual doesn't display the IC as "scaler", maybe you would like to look at the schematics, and you may get an idea if I'm on the right track? The question is if there are lots of data stored in those processors that needs to be flashed after replacement? Or maybe the micro processor take care of all data.

Best regards PAF

On Fri, 19 Feb 2010 01:30:03 -0800 (PST), powerampfreak put finger to keyboard and composed:

If you vary the aspect ratio, do the lines move?

Can the TV accept a DVI/HDMI input from a PC? If so, would it be possible to create a test pattern for troubleshooting purposes? What about a single vertical line with a user selectable colour and position, that flashes on and off once per second??? That should make the signal path easier to follow on a scope.

- Franc Zabkar