Samsung LN52A550P3F T-Con Board Color Problem

[Shane711]

I got this Samsung LN52A550P3F with a bad T-Con board. My colors are all messed up. So I assume it is an IC. There are 3 ICs but I am sure ICM1 is a memory chip. There is ICD1 (TPS65217a) and that seems to be a power IC so maybe not that. Then there is ICT1 (THF9301) which I can not find any information on what type of IC it is. So I assume it is this one. I am about to remove one from another working board to see if it fixes the problem, if it does I will order some new ones.

[dick_barton]

Re: Samsung LN52A550P3F T-Con Board Color Problem

Does the picture clear up if you only have one of the panel - Tcon ribbons connected? Have you cleaned up the LVDS cables since I seem to remember a fault just like this that was a cable problem.

[Shane711]

Re: Samsung LN52A550P3F T-Con Board Color Problem

No. I know it is not the screen because I actually have 4 T-Con boards. 2 are good and 2 are bad. So I need to repair the 2 bad ones.

[dick_barton]

Re: Samsung LN52A550P3F T-Con Board Color Problem

I don't think it's the screen either. The picture looks as though it has not only lost colour but also missing every 2nd pixel which was a problem with the LVDS cable to the mainboard in another thread. Can't guarantee that this is the case here but may be worth checking the cable.

Missed this in your first post.
You say you have some good Tcon boards so the fault must be with the Tcon

[Shane711]

Re: Samsung LN52A550P3F T-Con Board Color Problem

Cable is good. TV works fine with the good T-Cons. I am trying to fix a friends T-Con so I am using my TV to test it. TV works perfect with my T-Con board. I went through my parts and found another T-Con board I had written on "Needs to be tested" and it tested bad so now I have 2 I have to fix. Of Course my original T-Con board is good and I found another good one. But I don't believe in swapping out, I repair it.

I am also going to install a cooling fan so it does not happen again.

[Agent24]

Re: Samsung LN52A550P3F T-Con Board Color Problem

Before you try to swap the main processor...


Have you checked all the voltages from the onboard regulators ICD1, ICD2 are OK? Compare between a bad and working board.

Don't rule out ICM1 - it's a RAM chip, probably used as video memory, and you do have a corrupt image. It could be bad.

ICE1 seems to be a 24C64(?) EEPROM, probably the program for ICT1. If this was bad it may be loading wrong info into ICT1. Have you tried dumping this from both a good and bad board? Compare code? Try a brand new EEPROM and program with code dumped from a working board.

What is ICS1? Another EEPROM?

What are ICG1 and ICV1? Have you compared voltages at their pins between working and non-working boards?

[Shane711]

Re: Samsung LN52A550P3F T-Con Board Color Problem

OK, I did not notice that EEPROM. I will try that first. I can read and write to EEPROMs so maybe I will put in a new one. I am not at my shop right now but I will check to see what ICs are EEPROMs. And I will check all the voltages from a good board and bad board. I have not attempted to swap out any parts yet.

[aaronwt6]

Re: Samsung LN52A550P3F T-Con Board Color Problem

This is almost certainly the 'C102' issue on the main board. Do a search on here for C102 and you'll see tons of threads related to this board. I repair them daily.

Disregard. I should have read the whole thread and realized you said it works with another t-con. Interesting though as I've never seen one of those t-cons cause an issue like that.

[Shane711]

Re: Samsung LN52A550P3F T-Con Board Color Problem

I repair them everyday also, just did a main board about 1 hour ago. My problem is the T-con Board. I have about 10 Main boards laying around and I have people ship them to me for repair. Working on the T-Con board right now.

I do have some main boards I have not been able to fix after changing the T-Caps and power regulator next to them. But all the ones I have not been able to fix are ones I purchased for repair.

Oh, I have seen this many times. If your colors are bleeding it is usually an IC on the T-Con Board. I have also seen blocks on the screen and it was the T-Con Board. Blocks about 1 inch all over the screen. Like is was a puzzle and all the pieces were mixed up, replaced the T-Con board and it was fixed.

[aaronwt6]

Re: Samsung LN52A550P3F T-Con Board Color Problem

I just edited my post after ready through the thread. I should have done that first.

[Shane711]

Re: Samsung LN52A550P3F T-Con Board Color Problem

Well I swapped the EEPROMs and the Good T-Con board is still good and the bad T-Con Board is still bad so problem is not with the EEPROM. My next step is the main IC.

[Agent24]

Re: Samsung LN52A550P3F T-Con Board Color Problem

I still wonder if it's that RAM chip.

Bad VRAM on PC Graphics cards can cause similar image corruption patterns.

[Shane711]

Re: Samsung LN52A550P3F T-Con Board Color Problem

Right now I am getting double images. I can't seem to remove the main IC so I am going to have cut it off and put a new one on. It may be glued down.

[Diah]

Re: Samsung LN52A550P3F T-Con Board Color Problem

found another T-Con board I had written on "Needs to be tested" and it tested bad so now I have 2 I have to fix. Of Course my original T-Con board is good ...I am also going to install a cooling fan so it does not happen again.

what kind of bad the T-CON you found need to tested .. same fault as your OP photo?
T-CON to check not enough to place it and check. it need at least 1 day operation for unknown issue. because screen TAP fault at SMT CAP will effect the T-CON after awhile.

[saddle_au]

Re: Samsung LN52A550P3F T-Con Board Color Problem

Just a thought.

The odd or even pixel data seems to be missing and the color is out of sync. I'd check the first and second clock channels on the back of CNI1 to make sure the positive and negative drive for each is getting on the board. Reflow that connector and look for bad connections there.

The processor is from AUO, not sure if you can get it elsewhere.