IBM 5140 LCD screen issue

[jschulbach]

I've got one of the non-backlit screens and the bottom right corner is stuck 100% on, contrast slider doesn't effect it, the rest of the screen works great. I've opened the casing and there are 16 Toshiba T7778 driver chips on the board. The area of the screen that's stuck corresponds to 1/16th of the screen, so pretty sure it's the chip that sits behind that corner, or maybe something shorting pulling all those pixels to ground? Anyone have any tips on how to diagnose? The T7778 chips are surface mount, haven't worked on them before, but I've watched enough done that I could probably pull if off if that might be a solution, taking one from a donor board if I ever come across one.

I do have a working back-lit screen as well, so this is mainly a backup screen for me, but would be nice to fix it if it's possible.