I had the same situation with my cassette deck. I have a 84 GSL SE. I took all 3 components out, opened them up, blew out dust and then cleaned everything with electronic contact cleaner. All works well now. I was getting ready to replace the joystick thing, then shot the contact cleaner in there as well while moving it around, all works now. This may help you depending on how bad the situation is.

 

If you decide to replace it, I would like to buy it from you.