did it originally accept cd's when you got it? if the unit was shipped without a slug disc or shipping disc, it could have been knocked out of alignment, there suposed to have a fake cd in them to keep everything centered. bought a pioner unit from a flea market and after inserting a disc in it, it sounded like a grinder going off in the player. it was the laser driagging the disc from mis alignment, i to paid around 150.00, since i was furious i beat the hell out of the dash with my fist which in turn knocked it back in order! before, it scratched my pour beastie boys cd to pieces and after it worked for years until the car was totaled.