Grundig MCD 10 changer

[Cromus]

Hi i bought a car with a Grundig head unit and MCD 10 changer in it radio works fine but i have a problem with the changer what ever discs i use, original or copy, the cd changer loads from the magazine seems to scan the disc for a few moment the returns the disc to magazine and the error "SURFACE" appears on the head unit display anyone out there have any knowledge about these things? i know the MCD 10 is an old unit so it could be beyond repair but it seems such a waste, also on the subject of compatability if the changer is u/s are there other changers that would b compatable with the head unit
many thanks in advance for any help