I have the same deck-I needed another cassette deck like I needed a hole in my head.......but I thought it was a looker, and the suck face, a cool gimmick. It sounds very good in any event.
The main belt and the servo belt were bad. The main belt is flat out the easiest to replace of any deck I have encountered. I think it's one or at most two screws to remove and replace-and there's plenty of room to do this without more than removing the bonnet. Transport stays put. Easy peasy. If you have modest mechanical skill-it will be pretty obvious which screw(s), need to be removed.
I recall it being one screw, and just sliding the motor assembly out of a locating pin, cleaning of surfaces on the flywheel and pulley, slipping on the belt around the flywheel, then keeping a bit of tension on the belt as you hook the pulley onto it, and then re engage the locating pin, then replace the screw.
Now, the suck face belt-that's another story. I examined the mechanism, and concluded, it was not worth the hassle. The motor and associated geared mechanism, which has the tiny belt inside, is "held prisoner" in the guide rail system, as far as I can tell. I wound up disconnecting the associated motor wiring harness plug, then retracting the mechanism to reveal the knobs, and zip tied it in place. That is how I have used it for about 3 years.
I never found a service manual either.....
I have the following note by an AK member,( I think) I have no idea of who posted it:
"It's really silly easy to replace the belt and get it to work. If you haven't ordered the belt yet, get yourself a 21mm I.D. 0.8mm thick square rubber belt (I got mine from eBay seller "dalbanicorporation"). That's probably all you need."
Like many posts, it was clearly short on details-kind of a statement, suggesting that no further explanation is needed, unless you are a total noob-lol
If you discover a replacement method on the suck face mech, please share it with us-I would love to learn how. Thanks!