As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LIGHT SMOKE IN COCKPIT WITH PACS ON AND APU RUNNING. *S/D* APU WAS REPLACED DUE TO MASSIVE COOLING FAN FAILURE. FAN ROTOR FAILED, HOUSING WAS BROKEN AND MINOR FOD TO BOTH COMPRESSORS. FAILED APU REPLACED WITH NEW UNIT, OPERATION CHECKS NORMAL.