I press play and the head goes in and out repeatedly and pressing stop does nothing, have to power the unit off to get it to stop. I took it apart and the belt is a little loose but the capstan is spinning. Video link ...
The mechanism in the deck needs work and lubrication and what is happening is it is trying to reach a mechanical position but not being able to due to lack of proper torque from a belt or maybe hardened grease in the head base of other parts. I fix these on occasion here at my shop in Chicago area.