- check/replace U63 - de-soldered, tested chip, test passed, added socket, replaced with another good chip
- check/replace U26 (LS257) - de-soldered, tested chip, test passed, added socket, replaced with another good chip
- piggyback/check/replace RAM, but I would do that last - I got some screen changes when piggybacking but not anything useful
I left the system powered on for 40 minutes. No chips got hot or even very warm. I did notice the screen change when I pressed on the CPU. I also noticed the CPU (6502) was somewhat loose in the socket. I was able to pull it out with my fingers.
I'm not sure if that is an issue or not as it boots up in 80 column mode fine every time I try but I'll likely replace the CPU socket and test.