Samsung PS58C6500TK pink banding issue and more

[Baileybum1234]

Ok so I have a Samsung PS58C6500TK.

It had the pink banding issue please see attached pic.

I was looking at another forum and they suggested updating the control board firmware - I did this.

Excuse multiple post but trying to keep the stages I have taken separate.

[Baileybum1234]

Re: Samsung PS58C6500TK pink banding issue and more

This only partly fixed the issue. So I adjusted VS as the next step.

It was originally at 206.9 when it should be at 209.

I took it up to 209 then to 213 and back down to 209 and the fault remained during this process.

[Baileybum1234]

Re: Samsung PS58C6500TK pink banding issue and more

The issue is still a pink distortion that comes and goes with different colours.

Im starting to think there was more than one original problem.

Mostly at the top but some times running down through the screen.

There also looks like there might be wavy lines in the pictures. I think these happen so fast I cant see them there is deffinately something up!

There is distortion on the pictures due to mains Hz so please ignore the vertical bands thay are only in the pictures and not on the screen.

[Baileybum1234]

Re: Samsung PS58C6500TK pink banding issue and more

Best pic I have of the internal boards at the moment.

[Baileybum1234]

Re: Samsung PS58C6500TK pink banding issue and more

Ok,

I have triggered the test pattern from the control board. The image still has the same fault.

I made a video of the check:

https://www.dropbox.com/s/qlhumfdk1d...%2041.mov?dl=0

[tom66]

Re: Samsung PS58C6500TK pink banding issue and more

The wavy lines are a camera artefact due to the panel subfield refresh rate. You can ignore those (you may also see these if you "flick" your eyes across the panel.)
Check the Vscan, Vs, Va and Ve voltages.

[freakaftr8]

Re: Samsung PS58C6500TK pink banding issue and more

That does not look like the classic pink banding symptoms that the Samsung panels are attributing. This looks like a control board malfunction. These bars are going vertically across the screen pink banding with the classic symptoms usually span horizontally

[Baileybum1234]

Re: Samsung PS58C6500TK pink banding issue and more

Hi Tom,

I will test those today and see what I get.

Hi Freak,

While I'm there do you know of a way I can check the control board with out replacing it?

Cheers!

[freakaftr8]

Re: Samsung PS58C6500TK pink banding issue and more

Unfortunately I do not. If you can generate test patterns from the control board and like you show with the bars still there it looks like the right side is trying to mimic what the left is doing.

I suppose it could be something wrong with the panel also

[Baileybum1234]

Re: Samsung PS58C6500TK pink banding issue and more

The wavy lines are a camera artefact due to the panel subfield refresh rate. You can ignore those (you may also see these if you "flick" your eyes across the panel.)
Check the Vscan, Vs, Va and Ve voltages.

Hi Tom,

Tested results below:

Vscan: -199.7
Vs: 209V
Va: 55V
(Vb)Ve: 90.2

[Baileybum1234]

Re: Samsung PS58C6500TK pink banding issue and more

Unfortunately I do not. If you can generate test patterns from the control board and like you show with the bars still there it looks like the right side is trying to mimic what the left is doing.

I suppose it could be something wrong with the panel also

Gulp not the PANEL!!!

[Baileybum1234]

Re: Samsung PS58C6500TK pink banding issue and more

Hi Tom,

Tested results below:

Vscan: -199.7
Vs: 209V
Va: 55V
(Vb)Ve: 90.2

They all look OK to me. Any thoughts any one?

[tom66]

Re: Samsung PS58C6500TK pink banding issue and more

Presumably these match the sticker.
Try Vs around 215V max, and increase Ve and Vscan (make Vscan more negative) max +/-15V on each
Also if the Y-sustain has Yrr / Yfr controls mark their original position then play around with them--try Yfr first

[Baileybum1234]

Re: Samsung PS58C6500TK pink banding issue and more

Hi Tom yes they match the sticker.

I will have a play this evening.

[Baileybum1234]

Re: Samsung PS58C6500TK pink banding issue and more

Hi guys sorry its been a while.

Just been busy with work and decorating little ones bed room.

Tom I managed to do a few tests but struggled to find the Yrr / Yfr controls and test points maybe you could point me in the directing if there on this model? I did do some searching on Google and apparently some screens dont have this adjustment?

OK Results so far:

Vs: adjusted +/- 15v and there was no change at all.
Vscan: adjusted -15v and + 6v (POT wouldnt allow further) no change at all.
Ve/Vb: adjusted +/- 15v and there was no change at all.

While adjusting the POT's I was watching the screen pink part of the image in a mirror and also keeping an eye on the DVM at the same time.

Also added a few more pics for your viewing pleasure. Does the direction of the pink band give any clues? There is also a fizzing noise coming from varions boards and it looks like the pink distortion is at the same frequency as the fizz/hiss. Again any clues?

Cheers. :0)

[Baileybum1234]

Re: Samsung PS58C6500TK pink banding issue and more

When I run certain colours as a test background from a laptop the pink distortion doesn't show and the image is fine.

[Baileybum1234]

Re: Samsung PS58C6500TK pink banding issue and more

Any ideas folks still I'm still thinking on this one?

Happy Christmas by the way !!

[Baileybum1234]

Re: Samsung PS58C6500TK pink banding issue and more

I noticed a few threads having a little success by resoldiering the inductors?

Might be the next port of call and a good visual inspection.

[Baileybum1234]

Re: Samsung PS58C6500TK pink banding issue and more

So I pulled out these two boards for a visual inspection. I cant see any dry joints, anything burnt out or obvious.

Running out of ideas to be honest! I could reflow the Inductors on the off chance but only going by something I saw on another thread for an LG screen. One leg of the inductors are covered with a piece or rubber awkwardly but could pull this off if it was worth while.

Any further ideas out there??

Could I swap a ribbon to see if the pink fault moves or is this not possible?

Cheers

Jarrett

[tom66]

Re: Samsung PS58C6500TK pink banding issue and more

Inductors don't cause this fault on these Samsung sets, at least not seen any cases of it.
You're kind of stuck because Samsung doesn't support much tweaking unlike Pioneer sets.
You can't swap ribbons around, and anyway I doubt it would make any difference.
Perhaps all you can do is adjust Cell Light to reduce these artefacts, this will also dim the panel somewhat.