Hi fellas, I have a Toshiba 50u6863db (vestel crap) here belonging to a family member.
The TV was given me to repair (possibly) as it had developed a blank screen, just back lights and sound.
Upon further investigation it turned out one of her cats had sprayed on the screen as I could see it on the edge of the panel and tabs and it stank. Looks like it probably shorted the circuitry. I cleaned it up and still the same.
I initially suspected Tcon board as none of the test points were showing correct voltages. Tried removing one LVDS cable at a time, same result. I replaced the Tcon board and managed to get half an image if I disconnected the left ribbon on the Tcon. However with it connected same problem as before, so deduced a short somewhere on the panel driver board for that bad side causing the Tcon board to go into protection mode and shut down.
After much faffing about covering pins on the ribbon cable I whittled the bad pin down which connected to a diode on the bad driver board.
This diode was connected to VGL which was showing between 2.5v and 4v(kept getting different readings). Good side was showing -7.2v as it should.
After a lot of fault tracing I eventually found the issue was a short due to a burn out on one of the panel driver tabs.
I cut the burnt bits away and the short disappeared, VGL is now normal and now have a full picture. Unfortunately the issue that remains is a darker image on the bad side.
I have absolutely checked every component on the panel driver board and all are good, so it looks the damage to the tab ribbon is causing the issue. I suspect the small driver tabs on the left side of the panel are not getting proper power because of the damaged ribbon at the bottom left. Possibly VGL as this is what was shorted.
If I pull the ribbon on the bad side from the Tcon I get a perfect half image and blank the other side.
If I do the opposite both sides show nothing but random lines and no image, so that side seems cooked.
In all other aspects the image seems fine just the colour and darkness issue.
So here is my quandary, it's obvious the panel is beyond economical repair. Absolutely no way of repairing the damaged tab. The only option left is to pull off the tabs on the bad side and hope the drivers on the other side take over.
I suspect this may work.
If you look at the pictures you can see that the good side is attempting to drive the bad side as the brightness from the good right side is actually transcending the half way point (marked by the pen at the bottom)
It looks like the bad side is loading down the drivers on the good side, so it gets darker to the left. I'm hoping removing the tabs will allow the drivers on the good side to provide enough power to drive the bad side.
This TV will be scrap otherwise, so what's the opinion, do I go for it and pull the tabs?
The TV was given me to repair (possibly) as it had developed a blank screen, just back lights and sound.
Upon further investigation it turned out one of her cats had sprayed on the screen as I could see it on the edge of the panel and tabs and it stank. Looks like it probably shorted the circuitry. I cleaned it up and still the same.
I initially suspected Tcon board as none of the test points were showing correct voltages. Tried removing one LVDS cable at a time, same result. I replaced the Tcon board and managed to get half an image if I disconnected the left ribbon on the Tcon. However with it connected same problem as before, so deduced a short somewhere on the panel driver board for that bad side causing the Tcon board to go into protection mode and shut down.
After much faffing about covering pins on the ribbon cable I whittled the bad pin down which connected to a diode on the bad driver board.
This diode was connected to VGL which was showing between 2.5v and 4v(kept getting different readings). Good side was showing -7.2v as it should.
After a lot of fault tracing I eventually found the issue was a short due to a burn out on one of the panel driver tabs.
I cut the burnt bits away and the short disappeared, VGL is now normal and now have a full picture. Unfortunately the issue that remains is a darker image on the bad side.
I have absolutely checked every component on the panel driver board and all are good, so it looks the damage to the tab ribbon is causing the issue. I suspect the small driver tabs on the left side of the panel are not getting proper power because of the damaged ribbon at the bottom left. Possibly VGL as this is what was shorted.
If I pull the ribbon on the bad side from the Tcon I get a perfect half image and blank the other side.
If I do the opposite both sides show nothing but random lines and no image, so that side seems cooked.
In all other aspects the image seems fine just the colour and darkness issue.
So here is my quandary, it's obvious the panel is beyond economical repair. Absolutely no way of repairing the damaged tab. The only option left is to pull off the tabs on the bad side and hope the drivers on the other side take over.
I suspect this may work.
If you look at the pictures you can see that the good side is attempting to drive the bad side as the brightness from the good right side is actually transcending the half way point (marked by the pen at the bottom)
It looks like the bad side is loading down the drivers on the good side, so it gets darker to the left. I'm hoping removing the tabs will allow the drivers on the good side to provide enough power to drive the bad side.
This TV will be scrap otherwise, so what's the opinion, do I go for it and pull the tabs?
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