As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER APU STARTED, CABIN PAC IS BLOWING ONLY HOT AIR AND THE CABIN BEGAN FILLING WITH LIGHT SMOKY FOG. TROUBLESHOT TO SEIZED FRONT ACM. REMOVED FWD CABIN ACM IAW MM 21-51-00. INSTALLED EX ACM IAW MM 21-56-00. PRE-LUBED ACU IAW MM 12-10-01. OPS CHECKED GOOD. LEAK CHECKED GOOD.