As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CRUISE, PILOT REPORTED HEARING THE AUDIBLE GONG FOR THE FIRE WARNING SYS WITH NO OTHER INDICATION. TROUBLE SHOT SYS. REPLACED PILOTS AUDIO BOX. SYS OPERATED NORMAL ON GND. PERFORMED APPROX 30 MIN TEST FLIGHT. NO DEFECTS NOTED. ACFT RETURNED TO SERVICE.