I have a 1998 audi a8 that i recently bought and the stereo hasn't worked. everything lights up besides the little screen and it wont take tapes. all the buttons light up though. I took it to snows auto today and they said that im missing either the tuner or radio reciever that plugs in right by the six disc changer in the back. The six disc changer it still back there but does anyone know what the other part might be? it has an antennae hook up and what looks to be a power reciever. Any thoughts that could help are greatly appreciated!