Hey guys, so I'm in the process of trying to figure out what is wrong with my TI-83+, my brother ended up giving it back to me a long time ago broken and in this state, and just now I'm getting around to trying to fix it. I do have an identical board to compare to it however I'm having trouble finding a datasheet for the CPU. Which is a Inventec 6SI837, I'm trying to figure out what a pin is suppose to be doing, and where it leads. As I'm noticing that on my DEL button, (at least this is the one I've been watching) it tends to climb in voltage, up to .5mv then releases the voltage. Now it shouldn't be doing this, as with my working chip there is no voltage on that point. The other part of the pad reads 3.3v no problem. So it has to be stuck somewhere. I've gotten the calculator to boot shortly once, but I'm not really sure what I did as it's not repeatable.
Any suggestions and help would be fantastic!
EDIT: I forgot to mention, that I did indeed check to make sure that it's not the contrast setting. I also checked the wiring for the LCD to make sure that everything was connected, as these are known to get crimps in them then suddenly not work. I had to bodge some wires to fix a few points, but it is all connected and the LCD does indeed work fine.