Disk Error on 6 Disk Changer

I have 2002 LTZ with the Radio that has the built-in 6 CD Changer and is displays Disk Err. I tried disconnecting the Battery cable for an hour, but no difference. The Dealer wants to just swap it out for between $350 and $500. Does anyone know if there is a fix for these?.. and if its possible to get your Cd's back?.. Thanks!...jp