As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CREW UNABLE TO COMMUNICATE ON VHF. ISSUE STARTED WITH F/O POSITION, HOT MIC PROBLEM. ATTEMPTED RESETS OF AMU AND OTHER COMPONENTS AND PROBLEM SEEMED TO ALSO AFFECT CAPTAIN AND FIRST OBSERVER POSITION. REPLACED F/O HEADSET AND OPS CHECKED GOOD.