As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PACK MODE L LEFT PACK AIR CYCLE MACHINE HAD FAILED MESSAGE RECEIVED AND FLIGHT CREW NOTICED SMOKE IN COCKPIT AT TOP OF DESCENT. *S/D* PACK MODEL MESSAGE WAS DUE TO AIR CYCLE MACHINE (P/N 810209-3) SEIZING. HAMILTON STANDARD AND BOEING ARE WORKING TO IMPROVE THE ACM RELIABILITY. ACM TEARDOWN SHOWED THAT ACM FAILURE WAS NOT RELATED TO THE SMOKE INCIDENT.