Samsung UN55ES7500 Bad COF, T-Con, Panel Or Other?

[BeerDawg]

Samsung UN55ES7500FXZA TS01 (Late 2012 Model)

Thank you for your help! A little stumped at what this issue could be.

What I have done so far:
-cleaned the ribbons on the T-Con card
-tried adjusting the LVDS connector on both ends
-inspected source drivers (COF) connections look like new
-adjusted source drivers (pushed on them gently) warm to touch
-took VGMA voltage readings VGMA1=16.37v down to VGMA18=0.55v
all voltages went down from 1-18 incrementally
-went through all service menu test patterns
-the issue is on all inputs(antenna,hdmi)

All of this has resulted in no change or anything standing out to me as the problem. Unfortunately with all my research I have been unable to find a similiar problem. Usually the vertical bars are solid and across half or the whole screen.

I am trying to determine if this TV is fixable or not. Really like the TV.

The TV was taken out of manufactures packaging on put directly on a wall mount. Never dropped, hit or gotten wet.

Any help would be greatly appreciated.

I tried to include pictures of different media, but truly could use a short video to get full affect. There are horizontal bars within the vertical bars that appear to be going on and off. Not sure if the comes through in still photos.
The screen picture can be seen behind the vertical bars which is what I can't seem to find an example of in my research.

Thanks again for any information you can offer.

[BeerDawg]

Re: Samsung UN55ES7500 Bad COF, T-Con, Panel Or Other?

Has anyone seen a problem like this one? Or am I dealing with an unusual problem? More than likely the later with my luck. LOL!

Check pictures in post #1 for reference.

Thank you for your time and experience!

[maxvalutech]

Re: Samsung UN55ES7500 Bad COF, T-Con, Panel Or Other?

There are better brains than mine on here but for what its worth the verticals look to hold their size (both same width) but not their position from lhs edge of screen. Don't know the particular set but would first disconnect tcon outputs one at a time to see what then on screen, very carefully check lvds and tcon itself by replacement if cheap enough.

[attainteddragon]

Re: Samsung UN55ES7500 Bad COF, T-Con, Panel Or Other?

another small brain comment.

the effected area does not seem to correlate to the area that i would think that each cof chip covers, and when they fail, they normally pull the voltages down and mess up the refresh rate of the entire screen, so "may" be a t-con issue.

[BeerDawg]

Re: Samsung UN55ES7500 Bad COF, T-Con, Panel Or Other?

There are better brains than mine on here but for what its worth the verticals look to hold their size (both same width) but not their position from lhs edge of screen. Don't know the particular set but would first disconnect tcon outputs one at a time to see what then on screen, very carefully check lvds and tcon itself by replacement if cheap enough.

Thank you Maxvalutech for your thoughts!

I have tried disconnecting both tcon output ribbons. I experimented with one ribbon connected at a time and got the results I expected.

With the good half of the panel connected I got a good picture and the disconnected side was just solid white no problem area showing on the disconnected side.

With the ribbon connected to the problem side only I got a half screen picture with the problem sections still visible and the disconnected side was solid white. I even tried both ribbons on the bad side and got the same results for both ribbons.

I also tried to adjust the lvds cable as well. I first removed both ends and got no picture on the screen obviously. I then reconnected the cable and the picture had the same problem area. i tried wigglling the connections slightly and got the result expected. The screen picture went to all one color (pinkish). Then wiggled some more and got some kind of block pattern similiar to what I have seen for a loose connection. I connected both ends of the lvds cable firmly and the results were the same picture I had before messing with the cable. No movement or changes in the problem area were visble.

Will have to try and research more here about further diagnosing a faulty tcon board.

[BeerDawg]

Re: Samsung UN55ES7500 Bad COF, T-Con, Panel Or Other?

another small brain comment.

the effected area does not seem to correlate to the area that i would think that each cof chip covers, and when they fail, they normally pull the voltages down and mess up the refresh rate of the entire screen, so "may" be a t-con issue.

Thank you Attainteddragon for your thoughts!

The effected area does line up with cof ribbons. There are 14 ribbons alone the bottom of the panel and the problem area is above the second and third ribbons from the edge. Not sure if that's what you meant by, "correlating to coverage area of the cof chips".

If faulty cof chips were to effect the refresh rate of the whole screen I am not seeing that on mine. So that would be a positive. I am trying find away to determine if the cof chips are faulty because that would sadly mean the whole thing is junk. Would be really sad to have to dump this wonderful tv over a ribbon though.

I would like to try a new tcon board, but they are $200 for a chance at being the problem. I can't really afford that chance. Will have to research more here on how to diagnose a bad tcon. The gamma voltages looked good so that was dissapointing as determining the probelm to be the tcon board.

Was hoping someone on here had seen a problem like mine because I can't seem to find a similiar issue in any of the places I have looked so far.

[attainteddragon]

Re: Samsung UN55ES7500 Bad COF, T-Con, Panel Or Other?

unfortunately i can't offer much more advice on this one.
it is definitely not a gamma issue.
$200 is crazy for a t-con.

the only thing that may shed a little light on it is if you can get your hands on an ir thermometer and check to see if you are getting higher temperatures on the cof chips where the problem is. while your there, pressure on each one in the area of the fault may show a change in condition.

[Davi.p]

Re: Samsung UN55ES7500 Bad COF, T-Con, Panel Or Other?

From maxvalutech: "the verticals look to hold their size (both same width) but not their position from lhs edge of screen."
I think you're wrong, don't watch last Batman pictures 'cause it is a very old Cartoon and it has a thighter image than the entire screen. Surely there are those 2 COF chips bad or something near them that drive them, my advice is to check all the components on the panel's board without current (resistance, capacitance), and with current (know volts levels like Avvd=15v, Vcc=3,3v, Vcoms=6,xx V), maybe you find someone faulty..