CDR220 lights up, but no sound
 

2002 Boxster S CDR220 display backlight lights up but I have no numbers on the display, just the backlight and blank screen. There is no sound. Pressing buttons doesn't do anything. It has an Amp in the trunk. I know that in Mercedes, when the factory amps go out strange things happen. Is it the same on a 986? Or is the radio just shot?

If I recall correctly the CDR 220 has a removable faceplate. The electrical contacts can become dirty. I suggest that you remove the faceplate and clean the contacts. I believe that some people have found success with a pencil eraser.

It is also possible that the head unit or the amp is damaged.

check the fuse in the fuse panel also. Believe it is D9 for the amp & D8 for the radio. make sure all the connectors at the radio & amp is secure and plugged in.

If my 03 battery goes dead sometimes I have this happen after I jump it.
Try unhooking the battery for a minute and hook it back up. When I do this it works fine again.