Help with Samsung S42AX-YD01

[glen4cindy]

Hello,

I was given a Samsung S42AX-YD01 Plasma TV and told, it "doesn't work".

So, I assumed they were right, took the back off, and had a look. Everything looked good, so I plugged it in, and it came alive, but, the menu screen looked really fuzzy.

So, I hooked up a video source to it.

The 2nd issue is I don't have the remote, and the buttons and menu options do not respond as I would expect them to, but, I was able to use the Channel Down button to finally switch to the source I had the AV cables plugged into, and the screen came alive.

Though I have not tested all inputs, on the AV input I have tested, there is occasional flickering and flashing, but, overall, there seem to be no other issues. Also, with this video source, the menu screens aren't snowy and fuzzy.

From what I've been reading here an elsewhere could this be a possible issue with the Y Sustain board?

Thanks

[Shinju]

Re: Help with Samsung S42AX-YD01

Photos of the "fuzzy" picture and photos of the entire back with the boards exposed will help.

Are you looking at the Plasma screen up close? All of them look a little fuzzy until you get into a respectable viewing distance then you don't see any pixel flutter.

Anyway photos will help the pro's diagnose your issue better.

[glen4cindy]

Re: Help with Samsung S42AX-YD01

No, this was most certainly a very fuzzy snowy image. I cannot replicate it at the moment. It is intermittent.

The menu buttons are still acting funny, but, it could be that I have just not figured them out, or that it really isn't designed that you would adjust all the functions of the TV via the menu buttons.

Attached are the photos I have taken. I didn't remove the shield on the video section, nor remove the video section as it appears there is a board under that section. If it becomes necessary to narrow down the problem, I can accomplish this too.

[glen4cindy]

Re: Help with Samsung S42AX-YD01

I'm trying to attach photos, but, I keep getting errors. Trying again.

[Alastair E]

Re: Help with Samsung S42AX-YD01

On the Y-SUS, where it says 'AA5' there's a pair of MOSFETS.....

Check 'em for short.

[glen4cindy]

Re: Help with Samsung S42AX-YD01

I might be okay. I connected my Apple TV via one of the HDMI inputs and the picture remained perfect all along.

The only thing that worries me is heat. The screen feels pretty warm after it has been on for awhile. I've never had a plasma, and maybe this is normal, but, knowing what heat does to all the components inside a TV just worries me once re-install the back panel of the TV.

I would like to find a way to put some fans inside that would activate when the TV is powered on, but, I would then be worried about power surges too.

I suppose if they weren't designed with fans for airflow, maybe they don't really need it.

[glen4cindy]

Re: Help with Samsung S42AX-YD01

Hello.

I've had this TV off for a few days working on another unit.

I turned it on, and the "snowy" image returned.

I have attached photos. This snowy image was apparent on the menus and on the HDMI input I had connected.

This snowy image is not distinct and full and rich either. It is somewhat light as evident in the photos.

[glen4cindy]

Re: Help with Samsung S42AX-YD01

I also just realized that the label inside the TV says Samsung S42AX-YD01 but, the emblem on the front says Phillips, and the Amblight on either side is a Phillips thing. So, I hope I am providing the right set information here.......

[glen4cindy]

Re: Help with Samsung S42AX-YD01

I'm thinking this might be a cold solder joint somewhere.

As of now, the issue is "popping in and out" from a normal picture to what you see above.

So, when the picture is good, it's perfect, but, when it's out, it is dim and snowy.

Hopefully, this isn't a tab bond issue!

[Glitcher]

Re: Help with Samsung S42AX-YD01

Plasmas don't have tab bonds issues (you're thinking lcds) so you don't have to worry about that. And I don't think a defective panel could cause that problem, at least I don't think. I would be looking into the y-main and x-main boards. Could try checking for cold joints on those.

[Atlascopco]

Re: Help with Samsung S42AX-YD01

Hi - I have a very similar problem with my Samsung Plasma TV (PN58A550). I still have picture but the image quality is severely degraded (snowy, dim, hazy). It also is intermittent - every once in a while it comes in 100% brightness, colour, contrast, quality and then it'll snap back out to dim, hazy, snowy...

From what I've read, the ZSUS/X-Main is responsible for charging pixels and therefore could be the culprit - I just need some more direction. Am I right that this is the problem (Or is it the YSUS?) I've taken out the two boards but they appear (to the naked eye) to be fine. I have a volt meter but am not sure where to check.

[glen4cindy]

Re: Help with Samsung S42AX-YD01

This gives me some direction. Cam someone help me identify which of these boards is which?

[tom66]

Re: Help with Samsung S42AX-YD01

Looking from the rear of the set, X-main is on the right and Y-main is on the left.

[glen4cindy]

Re: Help with Samsung S42AX-YD01

Thanks tom66.

Would the X-Main be the place to start in this case?

Thanks.

[glen4cindy]

Re: Help with Samsung S42AX-YD01

Ok.

I may have removed the wrong board to get a better look at things. I removed the large board on the left.

It has two big round caps that have paper tops that look raised. Not sure if this is a normal appearance, but, I have attached photos for inspection.

If everything looks OK, I'll put all this back, and proceed to the other side.

Hope this helps. I have not been able to replicate getting the picture to lock back into a "good" picture so far. It seems to stay bad all the time now.

[glen4cindy]

Re: Help with Samsung S42AX-YD01

Any thoughts on these boards, especially the look of the 2 caps in the 2nd photo?

Thanks.

[tom66]

Re: Help with Samsung S42AX-YD01

Capacitors look OK, besides they would not cause your fault.
The cause might be a cold solder joint because it is intermittent. When working and when failed try checking the Vs and Ve voltages.

[glen4cindy]

Re: Help with Samsung S42AX-YD01

Capacitors look OK, besides they would not cause your fault.
The cause might be a cold solder joint because it is intermittent. When working and when failed try checking the Vs and Ve voltages.

I didn't see any of what I thought might be cold solder joints. There was one that might have been suspect, and I resoldered it, but, this did not fix the issue.

I have not had a chance to check the voltages, that is my next step. The intermittent nature of the fault seems to have gone away, and the fault seems permanent now.

I will be able to measure the voltages now, but, will not be able to measure them in the fault isn't present.

Someone mentioned the X-Main board might be a fault here. I have removed the X-Main board and have attached 2 photos below. I do not see any cold solder joints on that board, nor any components that look faulty.

Tom66 or others, is there something specific about this board that might cause this fault? Someone said it charges the screen.

Thanks for the help so far, and thanks in advance for continued help.

[tom66]

Re: Help with Samsung S42AX-YD01

The board is responsible for one half of the panel lighting and also the initialisation voltage (Ve or Vzbias.) Faults can cause dim images. Maybe the fault is in the module under that heatsink.

[glen4cindy]

Re: Help with Samsung S42AX-YD01

Thanks tom66. I appreciate the input. I removed the heatsink, but, being the module is just a very large IC, and there is nothing discernible about the module itself it doesn't appear to be possible to detect if it is actually at fault.

Under the heat transfer compound, there is only a shiny surface.

You stated that faults can cause dim images. I also have a grainy image but, I'm not sure that is fully apparent from one of my photos above.

In your opinion, do you think replacing this board would be the best starting point? That module does not at all look like it is a board replaceable item like a cap or some of the other components that are suggested board level repairs on this forum.

Thanks.