Anyone know what size idler tire is on the playback side of the mech? Mine is all cracked. Also, is there supposed to be a tire of some sort on the flywheel for the FF/REW? Currently it's metal-on-plastic and the FF/REW are slipping. The mechanism looks very similar to that used in the 9935K. I don't have that one with me here so I can't check if they're the same. FM is also weak and has a hum/buzz. AM is fine.