99er Forums

One of my systems works but shows garbled video, various ascii characters, etc. The other just goes straight to a black screen. It was making a noise but now it doesn't even do that. I just ordered a cf7+ and planned to use it on one of the ti systems, but it's looking like I may have to go buy another one.

Any way to possibly make one TI-99/4a out of the two systems?

You might try pulling the GROMs out of the 'black screen' computer and putting in your other one. I had an issue where in TI BASIC after some time a GROM would overheat and my character definitions started to go 'wacky'. TI BASIC/XB reload the character definitions at the start of each command line you enter, and I would see the characters change each time I'd enter a command line or a program line. But not while sitting there - if it happened when I didn't press enter, I'd suspect the VDP chip wasn't refreshing the DRAMS correctly, or a bad DRAM chip.