Samsung UE55JU6800K half screen dark

[Chrissygizmo]

Hello everyone, I've just been given a Samsung UE55JU6800K smart tv as it had white spots on the screen due to the led lenses falling off. After refitting them & putting the tv back together I thought it was a nice easy fix for a free bedroom tv , then I tried it before screwing the back into place. I realised that the right side of the screen was darker than the other side, I removed the screen again as I thought the backlights had failed but they are fine.
I put the screen back in place & turned it back on . The screen seemed to be ok again but different screens on the same program go light & dark. I will upload photos of this to try explaining better. Gogglebox was coming to an end & I started recording it on my phone, the picture is watchable until the screen changes to the advert . I've also noticed that when the full screen is light & watchable, the right side is still funny , you will notice that the people on the right of the screen look sun tanned (they aren't lol) .

Thank you in advance for your time 😊

[Chrissygizmo]

The last 2 pictures are the wrong way around, they are screenshots of the recording I mentioned, it is gogglebox sponsored by 3 then a change of image to the channel 4 & a map of GB with half the screen darker

[EazyBone]

This is exactly what you thought. The LEDs are bad. Sometimes LEDs will turn on for a few minutes and then go out then on and off etc, many phenomenon occur. You can test them and they are fine out back together and bad. Take apart and test bad. This is clearly a light issue though.

JJust change em out and I'm sure you'll be fine.

You can check connectors etc to see if loose but I've never been lucky like that

[Chrissygizmo]

I've had the screen off again and left it off for over an hour, the backlights stayed on with no issues, I've read on here that it could be something to do with the side cofs , but it says that this is a last resort as it's not reversible , if the screen has cofs on both sides you have to remove all the cofs on the dark side of the screen , i will try this as a last resort as the tv is still watchable

[nomoresonys]

This doesn't seem like a side cof issue, usually bad side cof looks like horizontal lines that don't go all the way across or a green kind of a mess on one side. Usually you can tell a bad side cof by inspecting the cof, a bad chip will look burnt, be misshaped, have a hole in it or maybe be much hotter than the others. Go ahead and inspect them. I would more suspect the tcon with these symptoms.

[nomoresonys]

Can clean the flat cables going from tcon to panel with a pencil eraser, sometimes it's dirty and causes problems. Also make sure cable from mainboard to tcon is clean and fits securely.

[Chrissygizmo]

Thank you for your input, I already tried cleaning the lvds cables with a pencil rubber I should of mentioned that in my post but I'm glad you cleared up the side ribbon part because I was almost ready to have a go at that , I will try the replacing the t-con board next , also I'm not sure if this would help to clarify the issue but I tried removing one t-con cable at a time & there was no picture or half picture when either side was removed, only a blank screen

[Chrissygizmo]

This doesn't seem like a side cof issue, usually bad side cof looks like horizontal lines that don't go all the way across or a green kind of a mess on one side. Usually you can tell a bad side cof by inspecting the cof, a bad chip will look burnt, be misshaped, have a hole in it or maybe be much hotter than the others. Go ahead and inspect them. I would more suspect the tcon with these symptoms.

It did originally have vertical lines, I used the sticky tape method to get past that , I've just removed the sticky tape & I will upload some pictures of it,

[nomoresonys]

Some tcon testing there, interesting how many ways a bad tcon can display: https://www.youtube.com/watch?v=_hOMC2qn6jY

[EazyBone]

Well that data would of been nice

[nomoresonys]

Yet here's another that has similar display as you show in the pictures that was bad backlight led/s. He did ok I guess but if replacing leds DO NOT use his same method, he was very lucky not to break the screen/panel: https://www.youtube.com/watch?v=raicZqT-qVo

[nomoresonys]

All these things just show that you should never jump to conclusions, start simple eliminate thru testing and go on.

[Chrissygizmo]

I've removed the side cofs & it's working spot on

[nomoresonys]

That's good, as you can see many issues mimic other issues, so it can be tough to tell exactly where the problem is just by observing the display. We always use extreme caution when removing side cofs because it's not reversible, this time it was the issue. Did you inspect those cofs and find a defect?

[Chrissygizmo]

That's good, as you can see many issues mimic other issues, so it can be tough to tell exactly where the problem is just by observing the display. We always use extreme caution when removing side cofs because it's not reversible, this time it was the issue. Did you inspect those cofs and find a defect?

I would love to say yes, I found a bad ribbon/cof but the truth of the matter is I'm really impatient, I was going to order a new tcon board for it but my impatience got the better of me & away I went pulling the cofs off , I just thought “FK IT I GOT IT FOR NOTHING” I know that's not the way to think about it but that's what happened, I did have an inkling about the top cof on the right side (bad side) I will insert a picture, I thought/hoped/wanted it to be the damaged one. I've put it next to another one of the cofs to compare. I've arrowed where I thought looked bad , just around the top edge, it looked slightly burnt compared to the rest, (VERY SLIGHTLY THOUGH) …
.

[Chrissygizmo]

this is what I was expecting to happen but I got away with it “THIS TIME” I need to be more PATIENT in the future because I've been I in the position of putting TV's back together after repairing them & I've managed to crack a couple of screens, torn part of a cof off & more stupid impatient accidents that I would prefer to forget DOHH

[nomoresonys]

Yes, I do think that cof is burnt, you did very well tracking down the problem. So many just throw them out and overflow the landfills. I have a 70 sharp that got this operation over 2 years ago, going strong, I don't notice any distortion on either side but it may be very slight.

[Chrissygizmo]

Yes, I do think that cof is burnt, you did very well tracking down the problem. So many just throw them out and overflow the landfills. I have a 70 sharp that got this operation over 2 years ago, going strong, I don't notice any distortion on either side but it may be very slight.

Thank you for your input, I found it very helpful as usual, I am going to post a problem concerning lines on a Sony KD-55XG9505 , hopefully you might be able to help me again especially with your username l