Originally Posted by ski555

I have repaired quite few of those. Here is briefly how to replace the belts.
Remove radio from car. Take the knobs out by pulling them. Remove the face plate. Grab between the holes and squize inward gently. Unscrew the locking brackets and remove. Now pull the radio out. Using a flat tip pry the covers out. Looking behind the face plate there are 4 small screws remove them (some of them are hard to reach). Now grab the cassete module and after disconnecting the couplings (2 of them) to the motherboard (main board) lift the cassette module out. There are two hinges where the cassete modules is attached. Remove the module from the hinges and it is out. Replace belts (about $6 and hard to find) and assemble in reverse order.
Good luck to you.