I'm unable to turn off the traffic news feature so radio progs constantly being interrupted. Also radio preset buttons 2 and 7 not functioning. I've tried all the usual reset options but no success. Also have no sound from door speakers. Otherwise all radio/CD features working ok with (tinny!) sound from dashboard speakers. Amp is Becker BE6600 (Porsche part 996.645.331.03). Faulty head, amp or both???