As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLIGHT RETURNED TO STATION DUE SMOKE IN THE CABIN. NO EMERGENCY WAS DECLARED AND THE LANDING WEIGHT WAS BELOW MAXIMUM. FOUND NR2 PACK INOP. NR2 PACK INOP SUSPECT NR 2 ACM WEAK INLET & EXAUST AIRFLOW WEAK. REPLACED ACM IAW AMM 21-52-21, OPS TEST CARRIED OUT, CHECKED OK.