Onkyo TA-RW11 How do the drive belts go around the large spindles?

The deck is over 20yrs. old and was excellent. I cannot use either deck to play recorded tapes. The decks don`t forward or reverse at normal speed, only the fast forward/reverse function works.
Upon going into the inside, of the unit, I observed what appeared to be either one or possibly two long,thin black rubber bands(broken/deteriorated) that seem to go around two movable/spin-able round cylinders that are adjacent/parallel to each other. There are four of these cylinders. Two for each deck/each side.
Is this all or part of the problem? How can I fix this? Do I need special tools? Where do I buy the parts?