OK - while jump starting my 2004 A4 B6 the other night, did a silly thing and accidentally crossed the jump leads on the terminals causing sparking and smoke around my battery. Once I realised and corrected, the car started OK, everything else works electrically, except the Radio, a Concert single CD edition, will not power on. I checked the fuse box, fuse here is OK, is it likely I've blown the fuse on the rear of the radio unit itself, or fused the whole stereo unit? I can't check this fuse on the rear of the radio at the moment as I do not have the removal tools. Thanks!