I was walking by a garage sale and they were selling a Mood Littly Phatty. I think a Tribute edition. He was saying $400 bucks but then when we tested it we realized it didn’t work. I have done some electronics work before so I thought this was a pretty good chance so I bought it for $200.
Does anyone know where I can go for details on fixing a machine like this? I’m not really sure where to start.
edit: It’s not a Tribute edition it’s a Phase II though.
Okay turns out it was just the power cable. So that’s pretty cool.
Few more questions:
Come on, $200 and only the cable was rotten!! 
Congratulations!
The knobs can be found in any DIY stompboxes (online) shop, like MusikDing (in UE).
As of the differences between the Sub37 and the Phatty, the Phatty has less possibilities: amongst others, no sub oscillator, no sequencer (but an arpeggiator), only one modulation bus (with only one auxiliary destination), less modulation options.
But as it’s a Stage II edition and not a Tribute, it can receive the CV out extension (only the Subsequent 37 CV has it) and I find its sound more rock‘n’roll. I was really excited by the Sub 37 announcement but decided to keep my good ol’ Phatty when I tried the Sub 37.
All in all I would say it’s a more direct instrument
I think you were very lucky! To me, the Little Phatty is an incredible synth, and I can’t be biased enough when I talk about it.
Really, really love it.
Made a simple video a week ago, showing some differences between Little and Sub Phatty.
Maybe it will make you comfortable with your choice. Although it has a few functions missing, the sound of the Little Phatty is huge.