Sony CCD-FX510 Camcorder

Sony CCD-FX510 Camcorder, about 13 years old. Didn't use it for 8 months, forgot to run it at least once a month. Now the tape transport doesn't work correctly. View finder, lens, basic electronic work fine. Tape will FF and REW, but slowly. Can't play old or new 8mm tape. Sometimes camcorder will eject the tape for no reason. I am able to repair electronics, but didn't want to open the case yet because I did open a 35mm camera once, turned out to not be a good idea. However we have a pretty good hardware lab at my new job. I think the problem is probably a belt adjustment or replacement? Does anyone have experience with this type of problem? Thanks for any advice you have.