Mitsubishi HS-422UR repair woes

[Lil Fuzz]

I've been working on an HS-422UR on and off for a bit now, but have not successfully got it working yet. When I first picked it up, it powered on but didn't do anything for a few seconds and would shut off. Figured it needed belts so stuffed it away for a bit until I ordered belts. Finally got belts, put them in, and it still does the same thing. I've been messing around with it for a while but haven't figured it out. The tape carrier runs in by hand perfectly and doesn't snag, no gears look damaged, I confirmed the motor runs when powered on by itself, and I cleaned the mode switch. I also checked to see if I visually saw issues with caps or solder joints, but didn't notice anything out of the ordinary. When I try to power on it doesn't make any noise like gears are trying to move or the motor is trying to spin. It doesn't help that I don't have a service manual either. Anybody have any suggestions?