TCON Board Failure? Lines / Blurry Image

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Samsung C34H892WGE 34" Monitor

34" CH892 Ultra-wide Curved WQHD Monitor.

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Gary Ribbans @garyribbans

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Posted: Jul 20, 2023

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TCON Board Failure? Lines / Blurry Image

I have removed the back of this monitor, applied freeze spray to the TCON board and when this is done the picture comes good. So I ordered a replacement TCON from China (AliExpress) only to have it arrive and perform exactly the same. If I use freeze spray on the replacement board it also fixes the issue.

Did I wrongly diagnose the fault or have I just got a bad item from China?

EDIT 1 - @oldturkey03 Thanks for your reply. Here are some photos as requested, hopefully they are clear enough and I have circled the area in red that results in a clear picture on the screen when freeze spray is applied.

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oldturkey03 @oldturkey03

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Posted: Jul 20, 2023

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@garyribbans we have to see what;s going on with your boards. Post some well focused, large pictures of your boards.

I do not think it's your T-con board but, it is of course possible. On one of the pictures you need to post, mark the area that you sprayed with freeze spray (excellent diagnostic tool :-)

This could be an issue with the driver boards and by freezing the T-con board you may decrease data rate or power to the boards. What do those lines look like when your monitor turns pon. Again, pictures will help. Adding images to an existing question

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@garyribbans thank you for the images. those will work. I am trying to identify the RT6820 IC which is made by Richtec.

What happens to your Screen when you disconnect that ribbon cable above it? Unplug it, disconnect that cable, then plug it back in and turn it on. Let us know what happens. We need to know what your screen shows. Then do the same thing to the other side. Always unplug the set while you remove those cables.This really looks like a panel error.

Jul 20, 2023 by oldturkey03

@oldturkey03 I unplugged the ribbon cables going to the driver boards one side at a time and re-tested. Both times the display was illuminated but completely blank. I am curious as to your method of thinking with this test, it always interests me to follow the logic that leads to a proper diagnosis. I often repair laptops and desktop computers but monitors are a new world for me.

Jul 22, 2023 by Gary Ribbans

@garyribbans I was thinking that it is possible that the panel (the LED drivers) aer shortening out the T-con board and causing higher current or processing draw and overheating the chip/circuit

Jul 22, 2023 by oldturkey03

@oldturkey03 I appreciate you taking the time to explain. While it looks like the repair is a flop at least I learned something. Out of interest apart from a blank screen when performing the left and right side ribbon cable disconnection tests what else could you expect to see and what would that tell us? Do my test results indicate a panel failure or do you now suspect the motherboard may be the fault?

Jul 22, 2023 by Gary Ribbans

@garyribbans commonly when you remove one of the ribbon cables the other side stays on, either just color/light and even images, if it is connected. The disconnected side is black of course. If there is an error on the driver board (panel errors are really seldom since most of those would be mechanical, like physical damage) Then it will shorten out the T-con board when plugged in it will mess with the whole screen. I separate the ribbons to determine which side the arrows is on, That way I know where to look. Yours is just weird :-) If it would have reacted the way I was expecting too, I would have thought we can try a Tape off to see if it is your panel. Those are a PITA to do because they are tedious. Something like this

https://www.youtube.com/watch?v=pfrRhw7-...

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

https://www.youtube.com/watch?v=atNmhu7H... is what I am referring too.

By the way the picture looks and behaves, I am leaning toward a bad LCD (driver boards) but the way your TV tests and behaves, it looks more like a mainboard. Good thing we are volunteers so we can afford wishy washy answers :))

Jul 22, 2023 by oldturkey03

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@garyribbans thank you for the images. those will work. I am trying to identify the RT6820 IC which is made by Richtec.

What happens to your Screen when you disconnect that ribbon cable above it? Unplug it, disconnect that cable, then plug it back in and turn it on. Let us know what happens. We need to know what your screen shows. Then do the same thing to the other side. Always unplug the set while you remove those cables.This really looks like a panel error. — oldturkey03
@oldturkey03 I unplugged the ribbon cables going to the driver boards one side at a time and re-tested. Both times the display was illuminated but completely blank. I am curious as to your method of thinking with this test, it always interests me to follow the logic that leads to a proper diagnosis. I often repair laptops and desktop computers but monitors are a new world for me. — Gary Ribbans
@garyribbans I was thinking that it is possible that the panel (the LED drivers) aer shortening out the T-con board and causing higher current or processing draw and overheating the chip/circuit — oldturkey03
@oldturkey03 I appreciate you taking the time to explain. While it looks like the repair is a flop at least I learned something. Out of interest apart from a blank screen when performing the left and right side ribbon cable disconnection tests what else could you expect to see and what would that tell us? Do my test results indicate a panel failure or do you now suspect the motherboard may be the fault? — Gary Ribbans
@garyribbans commonly when you remove one of the ribbon cables the other side stays on, either just color/light and even images, if it is connected. The disconnected side is black of course. If there is an error on the driver board (panel errors are really seldom since most of those would be mechanical, like physical damage) Then it will shorten out the T-con board when plugged in it will mess with the whole screen. I separate the ribbons to determine which side the arrows is on, That way I know where to look. Yours is just weird :-) If it would have reacted the way I was expecting too, I would have thought we can try a Tape off to see if it is your panel. Those are a PITA to do because they are tedious. Something like this

https://www.youtube.com/watch?v=pfrRhw7-...

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

https://www.youtube.com/watch?v=atNmhu7H... is what I am referring too.

By the way the picture looks and behaves, I am leaning toward a bad LCD (driver boards) but the way your TV tests and behaves, it looks more like a mainboard. Good thing we are volunteers so we can afford wishy washy answers :)) — oldturkey03

Samsung C34H892WGE 34" Monitor

TCON Board Failure? Lines / Blurry Image

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