Hey! I have a Sony STR-DH750 Stereo receiver, never had a problem with it until today. Was listening to a vinyl record ( via a Technics SL 1210-MK2), I heard a pop like a record skipping and the whole system lost all audio. All power is on, no errors that I can see, but I can't hear anything through the headphone jack or the speakers. I have the receiver connected to two older Bose shelf speakers and a new Polk subwoofer. Anyone know where I should start?! Thanks!