I have a ti-85 calculator and recently, a few lines of pixels at the very bottom have disappeared. I believe that they are dead pixels or some type of problem with the LCD connector, but I'm not sure how to fix this. I've tried rebooting the calculator, changing the brightness, and the mode+brightness trick and none of them work. I've seen several posts about a similar problem but they are all on different models and I'd rather not take a risk and break my calculator. How should I fix this?

The TI-85 and TI-86 both use a pair of flexible ribbon cables to connect the board holding the LCD controller to the LCD itself. One cable carries column signals, the other rows. Unfortunately, because inferior glue was used or because of the age of the calculators or because the design requires one of the cables to be folded back on itself to fit, the TI-85 and TI-86 frequently display exactly the symptoms you describe, with rows and/or columns dimming or going out entirely. Also unfortunately, we have found no reliable solution to the problem, let alone a solution that is easy to implement or which is proven to be a permanent fix. Sorry to be the bearer of bad news. You could experiment carefully with a heat gun and pressure on the area where the cable meets the side of the LCD, but we have not had much luck.

1) A solution for this problem is puteing someting like soft rubber to apply pressure on the ribbon cable and the LCD.
This is the easy way.

2) you cal try to pont a solder iron closse to the dead poin in the ribbon cable. do not thouch the ribbon cablre with the hot iron.

you can do this with the calculator on, but do not thouch anyting whit the iron. Don't use solder, clean the iron.

The iron sold have aroud 30w to 60w no more

see this video
http://www.youtube.com/watch?v=PZxneat6tF0