[villagetinker]

I would try a spray can (with a tube) of silicon based lubricant, cross your fingers and hope this works, if not you will probably need to have the machine taken apart and the wheels and shaft carefully cleaned and possibly polished. Now this is probably the easy cure, the other possibility is the mechanical linkage that starts and stops the wheels is jammed, this will probably be a much more complicated repair. I would normally offer my help, but I have never worked on a mechanical slot machine.