Samsung un55ks800df - Display slowly degrades

[p2computing]

Hello everyone,
I have a Samsung UN55KS800DF

When I turn the TV on the picture initially looks great

After 10 seconds or so, the bottom of the screen starts to show issues and it slowly creeps upward

Eventually the entire display is ghosting and distorted. If I power the TV off for a few minutes and power it back on, the cycle repeats with a good display that slowly degrades.

I have attached an image of the display after about 3 minutes of being powered on

Thanks in advance for all you do for us!

[p2computing]

Re: Samsung un55ks800df - Display slowly degrades

Update: Same issue whether the "One Connect" is plugged in or not

[alfatv]

Re: Samsung un55ks800df - Display slowly degrades

These are symptoms of bad t-con or panel.

[p2computing]

Re: Samsung un55ks800df - Display slowly degrades

Thanks! I will start taking things apart and look at the t-con for bad / blown components

[Davi.p]

Re: Samsung un55ks800df - Display slowly degrades

it is panel 99,9% not tcon, must check panel distribution boards and check if some diodes are present but much probably are the faulty gate drivers.. i have the ue46b7000 with similar issue, changed 2 tcons, same effect.. also changed two level shifters on the tcon, same problem..

[Storyteller12]

Re: Samsung un55ks800df - Display slowly degrades

This model has issues like this sometimes related to the diodes on the buffer boards.

It’s been discussed on this forum before. Doesn’t cost anything to try if your good with micro soldering. I would check this before ordering tcon etc.

[p2computing]

Re: Samsung un55ks800df - Display slowly degrades

Thank you so much for this info - Do you happen to have images of what I should be looking for, and where? I'm an amateur when it comes to TV electronics, but willing to give it a shot! I have a hot air station and decent soldering setup.

[Davi.p]

Re: Samsung un55ks800df - Display slowly degrades

Nothing much difficult, you are searching for a row of maybe 8/10 diodes, must check them all in resistance mode, if you find one that measures bad, or another way is to pick a frequencymeter and search for a signal about 20khz (CLK), some are 100hz (VST/STVP)

[p2computing]

Re: Samsung un55ks800df - Display slowly degrades

I've finally got some time to test this TV, and so far I've found only a couple VERY small diodes on the buffer boards that read (1) on the Multimeter, all others "in resistance mode" read between ~300 and ~500

I assume this means that is a bad diode and should be replaced, but I'm not sure of the size to order for replacement

[Davi.p]

Re: Samsung un55ks800df - Display slowly degrades

Always put the measures unit, 1, 300 are ohms? if yes first try to remove the lower ones and test the tv, if is ok then start searching a replacement

[p2computing]

Re: Samsung un55ks800df - Display slowly degrades

Thank you for the info! It's OK to remove diodes that are malfunctioning before immediately replacing?

[lotas]

Re: Samsung un55ks800df - Display slowly degrades

If we are talking about TVS diodes, then remove them and do not install anything, everything will work without them.