This probably won’t be the last time I use that headline. I got me one of these over the weekend. Unfortunately no power supply, and I’ll probably never seen one. They used the same dumb system the Atari 5200 did years afterwards, with the power integrated into the video cable. I did find a page with schematics to build your own, though.
I also got a boxed Mountain King for the 5200 at the same store. I used to play that on the C64 all the time.