My airplane came with 4 Bose jacks installed. It looks like the back seat jacks are on one circuit breaker and the front seat jacks are on another. All four have audio, but on the most recent flight the two in the front have no power so the headsets need batteries, even though the circuit breaker is not tripped. I've re-set the breaker but still no power. There are no inline fuses front what I can tell. What am I missing?