I recently bought a Sony CFD-65 which is very similar in design to this Sharp. It wouldn't play cd's at all when I first got it, so I cleaned the laser, regreased all the mechanism, and it was still dead. Then I noticed a very small leaf switch at the bottom of the mechanism that pushes onto a flap on the cd door. Once I'd straightened it out, it worked perfectly, so it may be worth checking to see if yours functions in a similar way