That'd be affecting the sound quality too. Sorry I can't help to fix, but I do have 4x 717s (same player without better video) that I could dig out when am doing my next project in which case I'd be happy to send it. Alternatively I have an unused working DV-505 (tad less refined than the 717/737 that you could try to see if you like the sound!).
Gut feeling is it has issues with the servo and transport, but replacing / repairing would cost the same as a fully working one from eBay. Having said this when I've had issues with the Pioneers it's down to capacitors rather than outright replacement of mechanisms…!
Mana Acoustics Racks / Bright Star IsoNodes Decoupling >> Allo DigiOne Player >> Pedja Rogic's Audial Model S DAC + Pioneer PL-71 turntable / Vista Audio phono-1 mk II / Denon PCL-5 headshell / Reson Reca >> LFD DLS >> LFD PA2M (SE) >> Royd RR3s.