I am wondering the same about my marantz 430. I can get the play, fast forward and rewind work with manual encouragement. It wiorks off and on. My unit is clean but had been in storage. any ideas out there?
Then it needs to be taken down and serviced by someone familiar with the deck. Grease hardens, old junk that had accumulated on the flywheel and idler drive turns into teflon. This is not a job you can take on.