I was able to resolve the problem with the prompt, it now correctly says C/W/M ?
BASIC loads to the point of asking for the memory size, but I cannot go any further.
The 16-character wide columns or random characters are still present, the prompt is pushed over 16 characters.
I believe all of the RAM is OK. Voltages in and out seem ok.
I believe the keyboard is OK (except for the 7 key?)
I swapped around the 8T26 chips on both boards, I traded chips' positions (there are 4 on both boards), there was no change. This tells me circumstantially that all 8 chips are OK, but the bus itself may be bad. At least that's what I plan to check next.
I also checked various points for voltages, I need to spend more time and compare with the schematic and chip data sheets.