Nope, not Atari. There was an extra Nintendo brick and a Midway brick in there.
So this PC-10 is going to just piss me off it seems. The wiring harness inside was for a Vs system. No big deal, because I had a correct harness.....so I thought. Turns out I have a Punchout harness, so it is missing the cable that goes from the CP to the small connector on the board. Dammit!
The monitor in the cab started smoking when I fired it up, so I yanked it out and put two more in. I threw in the Punchout! harness, power supply, and board, and fired it up. Nothing but white screens.

I know at least one of my boardsets works, but the PC-10 and both Punchouts gave the same result. Something is wrong here. I'm not sure I even want to mess with this stupid thing.
While I was out there, I messed with my candy cabs. Turns out the main one had no earth ground going to the switcher, so I rectified that. I need to get a full harness connected up in the second cab and test out the stock power supply in there.
I also got an extra 27" dual rez Nanao monitor in the buy, so I thought I would put that in my empty OK Baby candy cab....but it would mount up! I have no idea how the hell a monitor goes into that goofy cab. It must be missing some part of the hardware.