As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AROUND 10000 FT CREW HEARD A BANG AND THEN SMELLED AND SAW SMOKE. CREW DECLARED AND EMERGENCY AND ELECTED TO RETURN TO DEPARTURE WHERE THEY LANDED WITHOUT INCIDENT. MAINTENANCE INSPECTED AND FOUND PACK 1 ACM LOCKED UP. MAINTENANCE PLACED PACK 1 ON MEL IAW AMM AND ACFT IS GOOD FOR SERVICE.