As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CREW REPORTS ELEC SMELL IN CABIN WHILE BEING DEICED ( NOT DEICING FLUID SMELL). CAPT REPORTS A HEAVY BLACK SMOKE MOST PRONOUNCED BETWEEN DOOR 2 AND THE FIRST OW HATCH. CKD AND OPERATED ALL INTERIOR CABIN ITEMS, REMOVED CEILING PANELS, CKD WIRING AND DUCTS. RAN APU, ENGS WITH DIFFERENT PACK CONFIGURATIONS. CKD CARGO PITS AND NESTING SYS ALONG WITH ALL CB. NO SMELL OR SMOKE NOTED. ORIGIN CANNOT BE DUPLICATED.