As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING PREFLIGHT, STARTED APU & TURNED ON BOTH PACKS. MOMENTS LATER COCKPIT FILLED WITH SMOKE & ACRID ODOR. VERIFIED NO SMOKE OR ODOR FROM NR 2 PACK ON APU. SMOKE AND ODOR FROM NR 1 PACK WENT AWAY AFTER DESELECTING. TROUBLESHOT AND FOUND TO BE SEIZED ACM. RAI NEW ACM IAW AMM 21-51-08. OPS CHECK GOOD IAW AMM TASK 21-51-00-710-801.