As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON ENGINE START AT AAB, SMOKE DETECTOR AND HORN WENT OFF. INSPECTED CARGO COMPARTMENT FOUND NO SIGN OF SMOKE, PULLED CIRCUIT BREAKER TO CUT OFF HORN. FOUND CANNON PLUG ON NR 1 DETECTOR CORRODED, CLEANED CORROSION FROM CANNON PLUG, SYSTEM OPS CHECKED. GOOD PER MM CH 26.