UHF

I've got a KDC-W9027 (kind of flips down/out/back etc), and its gotten itself confused as to whether its open or closed and keeps trying to open more than it actually can which makes the most horrid crunching sound, it also doesnt flap all the way back up when i turn the ignition off as it THINKS its already closed.

Does anyone know how to "reset" it so it doesnt think its open/closed already? or is this a belt thing and i need to open it up to put the belt back in alignment or something?

I've tried closing it all the way up and powering it off for a while but nothing, so that makes me think its mechanical.