Samsung PS42C450B1W Picture Noise/Solarization

[Nevillet]

Hi All,

I'm just starting to look at this 7 year old Samsung PS42C450B1W that, on first power up the picture is fine. Then, after a few minutes, the picture becomes distorted with highlight noise and solarization effects. This is present on tuned images along with USB sourced video files.

On brief inspection there was no obvious visible bad caps, etc.
Looking at threads related to solarization, many point to the T-Con board (named logic board in this service manual)

Before I dive in and start measuring voltages, are there any general pointers for this kind of fault?

I've found the service manual which was too large to upload so have provided a link here:
https://www.dropbox.com/s/0znrcyicw8...dp_tv.pdf?dl=0







Many thanks

[dick_barton]

Re: Samsung PS42C450B1W Picture Noise/Solarization

Do a search of the forum for running the test pattern which will eliminate or otherwise any problem with the mainboard.

[Nevillet]

Re: Samsung PS42C450B1W Picture Noise/Solarization

I assume you mean the inbuilt test patterns accessed via the Service Mode.

If so, each test pattern displays varying amounts of the distortion I describe above.

Does this indicate the main board is suspect?

[dick_barton]

Re: Samsung PS42C450B1W Picture Noise/Solarization

No. It's disconnect the cable from control board to main board and place a jumper link on the control board but |I'm not 100% certain if its's pins 1 to 2 or 3 and 4 which is why I suggested searching the forum.

[Nevillet]

Re: Samsung PS42C450B1W Picture Noise/Solarization

I've disconnected the main ribbon cable (blue tab) and tried every permutation on jumpering the pins but get no signal on the screen.

I've searched the forum but can't see anything relevant

[dick_barton]

Re: Samsung PS42C450B1W Picture Noise/Solarization

I've disconnected the main ribbon cable (blue tab) and tried every permutation on jumpering the pins but get no signal on the screen.

I've searched the forum but can't see anything relevant

https://www.badcaps.net/forum/showthread.php?t=26790

[yokoono]

Re: Samsung PS42C450B1W Picture Noise/Solarization

Problems with gamma correction ?.

[Nevillet]

Re: Samsung PS42C450B1W Picture Noise/Solarization

Hi Dick, thanks again for your help.

Following the instructions in the post you cite I am in service mode born out of the T-Con board.

It is cycling though the various test patterns and displays the solarization distortion I described above.

What can be concluded and Is there a component level fix possible for this fault?

[yokoono]

Re: Samsung PS42C450B1W Picture Noise/Solarization

What writes on the IC surrounded by red?

[dick_barton]

Re: Samsung PS42C450B1W Picture Noise/Solarization

If may well be an issue with the control board needing to be replaced.

This looks like a possible replacement if you want to try changing it.
https://www.ebay.co.uk/itm/T-CON-LVD...sAAOSwxDxclgZW

[Nevillet]

Re: Samsung PS42C450B1W Picture Noise/Solarization

Hi

The IC you indicated has no markings (checked with microscope)

[Nevillet]

Re: Samsung PS42C450B1W Picture Noise/Solarization

I've just ordered the t-con board from eBay.

BTW: It still has the same fault: When it first turns on it's fine but after a couple of minutes it exhibits the solarisation effect fault.

[yokoono]

Re: Samsung PS42C450B1W Picture Noise/Solarization

I think the gamma correction is faulty.

[Nevillet]

Re: Samsung PS42C450B1W Picture Noise/Solarization

I think the gamma correction is faulty.

Forgive my ignorance: Which board should I be looking at re gamma correction?

[Nevillet]

Re: Samsung PS42C450B1W Picture Noise/Solarization

I installed the replacement T-con board but unfortunately the symptoms remain the same:

Good picture immediately after switch on. After a couple of minutes the picture becomes distorted on the highlights, similar to solarization.

Can you suggest any next steps?

Many thanks.

[dick_barton]

Re: Samsung PS42C450B1W Picture Noise/Solarization

That's a pity. Can you check your voltages as given on page 56 of the manual. The correct voltages for your set will be as given on the voltage label on your set.