Audi A4 - Symphony Radop / CD PLayer?

The radio/CD/cassette player in my A4 ( 2002 ) does not switch on - there is just a dull red glow, only visible in darkish conditions in the normal display - any suggestions _ I have removed fuse 39 and it makes no difference, the fuse is OK, bujt I suspect some sort of power problem. Any suggestions.