As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) SQUELCH KNOB ON INTERCOM WAS NOT ADJUSTING SQUELCH SO THAT PILOT COULD ALWAYS HEAR ENGINE NOISE OVER HEADSET. REMOVED & REPLACED INTERCOM WITH SAME PN UNIT FROM ANOTHER PLANE. FUNCTION TESTED SATISFACTORY & RELEASED BACK TO SERVICE.