Years ago I developed what I call "TIP Modules" for my personal use on my Jokerz! machine. The TIP Modules replace those really hot transistors and resistor mess on my MPU board, as well as provide LED diagnostics. You can see them in-place in the attached pics.
I'd like to improve my design into a pluggable module, but don't want to take my Jokerz machine off-line while goofing around with the new TIP Module changes. Thus I'd like to purchase a System 11 MPU board for some additional research and testing.
The MPU can be missing parts, damaged/broken, not working, et cetera. I mostly want it to test fitment with the new pluggable design.