Tricky Alpine CD Changer Problem?

Hi, I am new to the Zone. I just bought a 2001 freelander td4 estate. I put 6 discs in the cartridge and it checks them and then selects 1st track but there is no sound. There is sound when I use the radio but not when I switch to CD mode. I can hear the changer switching when I ask it to but it does the same thing with each disc. It goes to the disc and song selected and then nothing more. There are no error codes either it just shows cd and track number but no sound and no indication on screen that it is playing either. It's an alpine unit and I just bought a new one because I thought it was a problem with changer but the new changer did not help. I have searched the site but could not find anything like this posted.

Thanks,

Aaron