Hi,
I'm new here - great forum! I've got a strange LCD problem. It's a Samsung A756 40" LCD which is quite a rare model here in the UK though it seems to share components from many other models of the era. It's about five years old.
I'm in the fortunate position of having access to two of these TV's which were purchased at the same time from the same retailer. They are identical. One is working fine while the other starting exhibiting a completely distorted (random noise) picture. I managed to fix this by applying heat to the left most panel tab. But now I'm left with the issue you can see in my attachments.
I have systematically swapped boards one at a time with the working TV and there was no improvement. Therefore I know that the TCONN, main board, PSU and all connecting cables are not at fault. No amount of ribbon cable and tab manipulation, heating or cooling will change the picture at all. I have also flexed the panel with no change.
One other clue - if I remove ribbon cable 3 (counting from the left) the right hand side of the panel goes completely white with no distortion. This suggests to me that each sub pixel can be driven to maximum value correctly from the chips on the tabs. Is my logic flawed?
Has anybody seen anything like this? I've come so far with the repair, it would be a shame to have to scrap it now. At least I would have spare boards for my other TV I guess!
I'm new here - great forum! I've got a strange LCD problem. It's a Samsung A756 40" LCD which is quite a rare model here in the UK though it seems to share components from many other models of the era. It's about five years old.
I'm in the fortunate position of having access to two of these TV's which were purchased at the same time from the same retailer. They are identical. One is working fine while the other starting exhibiting a completely distorted (random noise) picture. I managed to fix this by applying heat to the left most panel tab. But now I'm left with the issue you can see in my attachments.
I have systematically swapped boards one at a time with the working TV and there was no improvement. Therefore I know that the TCONN, main board, PSU and all connecting cables are not at fault. No amount of ribbon cable and tab manipulation, heating or cooling will change the picture at all. I have also flexed the panel with no change.
One other clue - if I remove ribbon cable 3 (counting from the left) the right hand side of the panel goes completely white with no distortion. This suggests to me that each sub pixel can be driven to maximum value correctly from the chips on the tabs. Is my logic flawed?
Has anybody seen anything like this? I've come so far with the repair, it would be a shame to have to scrap it now. At least I would have spare boards for my other TV I guess!
Attached Files
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