As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) ON DEPARTURE, FORWARD CLOSET SMOKE DETECTOR ACTIVATED AND ACRID SMELL DETECTED IN CABIN. RETURNED WITHOUT FURTHER INCIDENT. FOUND BLEED AIR DUCT AT AIR DISTRIBUTION MANIFOLD LT SIDE A-DRIFT, SECURED DUCT AND LEAK CHECK CARRIED OUT. AS A FURTHER PRECAUTION ON ARRIVAL, AIR DUCT P/N 65-54467-1 AND MIXING CHAMBER P/N 65-54470-2 REPLACED WITH OVERHAULED UNITS.