As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
SMOKE ALARM ACTIVATED DURING CLIMB OUT. SMELL OF €ŒHOT PACK€? WAS NOTICED BY FLIGHT ATTENDANTS AND PILOTS, ALTHOUGH PACK TEMPS WERE NORMAL. RETURNED TO FIELD. (FLT#5913) CLOSED LH AND RH ACMS WERE REMOVED AND REPLACED. OPS CHECK AND LEAK CHECK OF BOTH ACMS. NO SMOKE NOTED IN CABIN WITH BOTH PACKS SELECTED TO ON AND HIGH HEAT.