As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHILE SITTING ON THE RAMP WAITING FOR A PAX WITH THE APU RUNNING & BLEED AIR ON, SMOKE BEGAN FILLING THE CABIN. REMOVED THE ACM FROM THE AIRCRAFT. PERFORMED A TORQUE CHECK OF THE TURBINE. FOUND THE TURBINE SEIZED IN PLACE, FAILING THE TORQUE CHECK. REMOVED AND REPLACED THE ACM COOLING TURBINE WITH AN OVERHAULED ASSEMBLY. INSTALLED NEW GASKETS AND SLEEVES AS NEEDED. SAFETIED CLAMPS AS NEEDED. PERFORMED AN OPERATIONAL CHECK. OPS CHECK GOOD AT THIS TIME.