There doesn't seem to be any Sony fans here but this unit was given to me for my work car. I have the CDX-C5000X head unit connected to a MX4045 amp and a CDX71 changer. I had the head unit and amp installed professionally. Here is the problem. The radio works fine but when I try to listen to either the cd player in the head unit or the cd changer the cd will spin up and the time counter will be displayed but there is no sound. Any Suggestions?