Cd Changer malfunctioning

Greetings MB's I have a problem with my 1998 e-320 wagon's cd changer. The changer skips and won't play every (commercial) cd. The cassette player is now acking up. Are these problems with the head unit or the head (for the cassette) and the cd changer? What type of repair is required? Should I take to MD dealer or ship off to a repair house?

Thanks for your help

I have the same problem with my E320 Wagon. Have looked on eBay for a replacement, but they are going for around $200 for a used unit. Any hints on repair out there?