What was found
WHEN THE AIR CONDITIONER WAS TURNED ON, THERE WAS A "POPPING" SOUND IN THE INTERCOMM SYSTEM IN CREW HELMETS. THIS WAS ACCOMPANIED BY AN "AUX BATTERY" LIGHT. INSPECTION OF NR 2 STARTER GEN SHOWED SIGNIFCANT WEAR OF BRUSHES AND AN UNUSUAL WEAR PATTERN ON THE COMMUTATOR. STARTER GEN WAS REPLACED. NOISE WENT AWAY. THERE WAS A SECONDARY DEFECT WITH THE CURRENT LIMITER FOR THE SYSTEM. THAT UNIT WAS REPLACED AND ALL FUNCTIONS RETURNED TO NORMAL.