Hello, I figured I would start a topic for my custom case/ATX conversion of my Quadra 650! I got the logic board from just.in.time for $5 dollars, in untested condition. I actually found the matching connector for the power connector on Mouser! I ordered that, and I used clip leads for a first test, set up for hard power. I connected a speaker, and applied power. The board chimed, and it booted to the question mark. Yay! The board was good. Then, I connected an external scsi hard drive, which was read and it booted.
Now, I'm going to assemble the proper cable so I don't have to use clip