Hello all! This is my first post!
Well, I've a really strange problem. I've bought a TI83+ from internet, that has just one vertical line blank (blank all the times, not even responding to contrast adjustment).

I've used this calc for a while, and switch back to my old casio FX570ms (more usefull with the "engineer mode" and resolvent stuff).

Now I powered up the TI and 3 lines are completely dead!

I've readed that ribbon cable might be bad, but I've tested the resistance for each cable and its around 1.3 ohms, so I think thats not the problem.
Also, I've tested applying gentle pressure on the connectors of the flat ribbon cable that goes straight to the LCD and the controller IC, and nothing changes!.

There seems to be a "loose" connection between the driver IC and the LCD, since if I put some black pixels over those lines, in some areas, a "pixel" might turn on. For example, if I press "MODE", and select Radian, but focus over Degree, some pixels appears to be turned on (displaying correctly "Radian").


In the image you can see those lines (contrast set to 9). Also some kind of contrast degeneration near those lines, weird!

I've told that 3 lines were dead, but appears that one line came back from death while manipulating the board! (its not static charged, weird).

Anyone knows anything about this?

Thanks!

This is a stereotypical failure of the fine-pitched cable that goes to the top of the LCD. It occurs as the conductive adhesive that affixes the cable to the LCD ages and breaks down. Unfortunately, we have tried hard on the TI-82, TI-83, TI-85, and TI-86 to fix this problem, and we haven't succeeded in any fix that lasts more than a few weeks. The general solution should involve an even application of heat, but none of the methods we've attempted (hair dryer, heat gun, soldering iron) have done the trick.