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Old 01-17-2022, 03:38 AM   #1
angelos
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Default LED Panel repair! COF IC's

So i have been watching a lot of those panel repair videos. Not the one with the bypass method cutting the CKV lines but the videos where a voltage is missing to one of the side COF IC's. This is what happened...
I got in a Telefunken 32" LED TV, when you start up the set the Telefunken logo comes up but soon fades to blue, the whole screen becomes the faded washed out blue. The corners of the LED panel also have black corners. It almost looks like water got into the set but this is not so.
I got the set in the service position. (turned the panel upside down so that i can get to the side COF IC's test points) Connected the LVDS cable to the mother board and then scratched off the insulation on the test point of the COF IC's so that Ii can take measurements.
Now I already googled the COF IC's test points voltages so i knew what to expect.
Switched on and took measurements, I noticed the VGH reading was measuring -8V DC. Took my magnifying glass and inspected the circuit that is inside the glass that goes from the side cof down the side to the bottom COF IC's and behold that circuit was open circuit. I could see little splotches. I dont know how to explain it better but the conductive material had disappeared in several places. So i had to put in a wire. I quickly soldered a super thin wire onto the pad of the side COF IC and supported it with sticky tape glueing it to the glass leading to the bottom and soldered the other side to the VGH test point on the scalar board (Board at the bottom of the screen that is attached with the COF IC's). I reassembled the unit and powered up the set. Voila, 100% image. We went from a scrap set to a profitable repair.
And do you know how many sets like these I have returned or thrown away, plenty..... this is a common problem
Perhaps this helps someone in this forum.
If you have any questions just holler.
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Old 01-17-2022, 05:04 AM   #2
nomoresonys
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Default Re: LED Panel repair!

Well done angelos, youtube has some good videos on this too.
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Old 01-17-2022, 07:23 PM   #3
handsworth
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Default Re: LED Panel repair!

Can anyone post a link to any of these videos? I'd like to learn how to do this.
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Old 01-17-2022, 07:42 PM   #4
dskall
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Default Re: LED Panel repair!

Helps if you speak Hindi or Tagalog etc.
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Old 01-18-2022, 05:34 AM   #5
angelos
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Default Re: LED Panel repair!

https://www.youtube.com/watch?v=HNsI8Lx0ro4

Here is the video. Remember that you get a variety of symptoms i you have a voltage missing. From a screen that goes blue, to a dark screen to a screen that flickers like a vertical hold issue sort of.
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Old 01-18-2022, 11:01 AM   #6
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Default Re: LED Panel repair!

Quote:
Originally Posted by dskall View Post
Helps if you speak Hindi or Tagalog etc.
I hear that, like pullin teeth finding it in English, click nope, click nope, click nope, crap I give up.
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Old 01-18-2022, 12:42 PM   #7
angelos
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Default Re: LED Panel repair!

It's very seldom you get someone that shares their secrets so we should appreciate what is available on boob tube. Even though I don't understand I can make out enough to take instruction. I mean, my mentor is the you tubers. You can't go anywhere in my idiot country and get led repair training because the folks here are terrified if they give out their secrets they will go hungry
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Old 01-18-2022, 02:53 PM   #8
handsworth
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Default Re: LED Panel repair!

Quote:
Originally Posted by angelos View Post
https://www.youtube.com/watch?v=HNsI8Lx0ro4

Here is the video. Remember that you get a variety of symptoms i you have a voltage missing. From a screen that goes blue, to a dark screen to a screen that flickers like a vertical hold issue sort of.
Thanks, thats a start. I got some bad panels I will try it on and continue to learn more. The help is appreciated.
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Old 01-23-2022, 05:18 PM   #9
Farasa
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Default Re: LED Panel repair! COF IC's

Hi Angelos ...i have a panel that has a dark image on the left side and is slow...it has 3 cofs on each side ..i allready checked Vgh and Vgl....no problems there any advice will be appreciated
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Old 01-23-2022, 07:49 PM   #10
nomoresonys
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Default Re: LED Panel repair! COF IC's

at Farasa. Reminds me of bad tab bond contact from buffer board to panel, maybe not. Try cleaning the lvds cable contact pins and same mainboard pins where it plugs in clean the other end too that goes to tcon or buffer board if there is no stand alone tcon, be careful they are delicate, some use iso alcohol and qtip, some use a pencil eraser. Make sure you position them just right when you plug them back in.

Last edited by nomoresonys; 01-23-2022 at 07:53 PM..
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Old 01-23-2022, 07:58 PM   #11
nomoresonys
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Default Re: LED Panel repair! COF IC's

Tab bond shimming: https://www.youtube.com/watch?v=purk_SyiT44
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Old 01-24-2022, 07:36 AM   #12
hasitha prasad
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Default Re: LED Panel repair! COF IC's

Quote:
Originally Posted by Farasa View Post
Hi Angelos ...i have a panel that has a dark image on the left side and is slow...it has 3 cofs on each side ..i allready checked Vgh and Vgl....no problems there any advice will be appreciated

I've recently repaired a similar issue on a 4k 42 inch tv. Just look at my reply on the bottom of this thread. it might help you.
https://www.badcaps.net/forum/showth...ight=side+dark
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Old 01-24-2022, 09:18 AM   #13
nomoresonys
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Default Re: LED Panel repair! COF IC's

Yep, it's been thoroughly covered, read and do the homework becuz it can't be undone: https://www.badcaps.net/forum/showthread.php?t=49281
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