CD Changer Problem

[Dakes55]

My 6 disc cd changer in the boot is not working, I only just tried it out as it never had a cd cartridge when I got the car, so I put some cd's in the cartridge exactly the right way up, pushed the cartridge into the player and tried it out, I pressed the cd button twice on my audi concert 2 radio and it showed that the disc was being loaded and actually playing, but its not, I can select different cd's on the changer but they are not playing, even thought the radio shows that they are, I turned on the radio while holding down the cd button and "Connect" shows up on the radio screen, as I understand this is correct, I have done some tests with VCDS and its not showing any problems, I cant eject the cartridge from the cd changer as it seems like there is no power??

I have also connected another identical cd changer that is known to be working ok, but it still has the same problems, any ideas on this guys??