As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AWAITING TAKEOFF, PILOT TURNED ON CABIN LIGHTS AND NOTICED SMOKE FUMES IN COCKPIT AND CABIN. TURNED OFF VENT BLOWED AND CABIN LIGHTS AND RETURNED TO RAMP. IT WAS DETERMINED THAT THE POWER SUPPLY (BALLAST) HAD FAILED AND CAUSED THE SMOKE. POWER SUPPLY WAS RELACED AND LIGHTS OPERATED NORMAL. (K)