I have an Alpine CDA9856 head unit installed in my 2000 Jeep Cherokee. Factory speakers in the doors. Polk MMC525's in the soundbar. All was well until yesterday...the head unit shuts down after approx 10 seconds. By shutting down, I mean no sound out of the front and rear speakers. The display works..the sub works...could a single blown speaker cause the head unit not to output sound? Thanks in advance.