Troubleshooting Sansui turntable FR-Q5

This turntable is almost exactly the same as FR-D4, and manual is similar, but I can't find any troubleshooting info on either one. The problem is thus: turn power on, platter rotates, 'computer' light winks as it should, then platter stops after about 10 seconds. It has a start/stop switch that you press which is supposed to lift the arm and automatically place it on the record, but that is not functioning. Any ideas?

clutches, rubber disks, belts in the tonearm drive can be broke or worn out

Service Manual available from Vinyl Engine