As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) DURING THE MORNING STARTUP OF THE AIRCRAFT AND THE GPU HOOKED UP, WHEN POWER WAS SELECTED ON THE AIRCRAFT IT BEGAN TO FILL WITH SMOKE AND FUMES. POWER WAS SHUTDOWN, THE FUMES AND SMOKE DISSIPATED. MTC IS CURRENTLY INVESTIGATING. RT RECIRCULATION FAN REPLACED AS REQUIRED IAW AMM 21-24-01 PB401.