As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PRIOR TO TAKEOFF, THE SENIOR FLIGHT ATTENDANT REPORTED SMOKE IN THE CABIN. MECHANIC’S INVESTIGATION DETERMINED THE SMOKE IN THE CABIN WAS DUE TO AN ELECTRICAL MALFUNCTION CAUSING BOTH PACKS TO TRIP OFF. CABIN THEN FILLED WITH ENGINE BLEED AIR BYPASSING BOTH AIR-CYCLE MACHINES.