As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON GROUND WITH APU RUNNING AFTER SELECTING MAX COOL THERE WAS A LOUD POP FOLLOWED BY SMOKE IN THE COCKPIT. RAN AIRCRAFT. FOUND COCKPIT ACM TURBINE SEIZED. REMOVED COCKPIT ACM IN REF TO CE750 M/M CH 21-51-00 MAY 11, 2006. INSTALLED NEW ACM AS REQ OPS CHECK GOOD, LEAK CHECKS GOOD. ALL DONE IAW 750 MM CH 21-51-00.