Anyone had this problem? The symphony II in our A4 (B6) wouldn't switch on all of a sudden, though I think I could hear the CD loader mechanism make some sort of whirring noise. Removing and re-inserting the fuse, which looked fine, from the main fuse box must have reset something as it then switched on fine and hasn't given any trouble since. Is this a known problem with the symphony head unit? The warranty runs out in January so I'm keen to get any lurking nasties fixed before then. Thanks.