Yamaha SY-1 Tuning procedure

Hello, I recently got my hands on a Yamaha SY-1 and while every function works it’s tuning has drifted away quite a bit and it’s scaling is off on lower octaves. Top it off with intermittent key contact problems and I figured I’d try my hand at tuning it up. Anybody have any advice on what components or trimmers inside will help me? I have the service manual and a multimeter but I’m not sure how big of a repair this would be. Any help is greatly appreciated!