What was found
CAPT AUDIO CONSTANT STATIC ON SPEAKER AND MINITEL HEADSET - NO SPARE IN FLIGHT DECK. CONSTANT BUZZING SOUND ON BOTH CAPT'S AND FIRST OFFICERS SPEAKERS AND HEADSETS ONLY WITH CABIN INTERPHONE SELECTED. REPLACED AMU AND CIDS DIRECTOR 1, NO HELP. VERIFIED ALL SERVICE INPH JACKS GOOD. STILL BAD AND NEEDS MORE TROUBLESHOOTING. REPLACED NR 1 ENGINE MAINT INTERPHONE JACK, CHECKS NORMAL.