As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
HEARD A RUMBLING SOUND AND THEN THE SMELL OF SMOKE. TURNED THE BLOWER SWITCH TO OVRD AND NOISE AND SMOKE BOTH CLEARED. REMOVED AND REPLACED EXTRACT/BLOWER FAN 20HQ PER AMM TASK 21-26-51-400-001A. PERFORMED AN OPERATIONAL CHECK OF AVIONICS EQUIPMENT VENTILATION SYSTEM, PER AMM 21-26-00-710-001A, SYSTEM OP'S CHECKS GOOD. THE AIRCRAFT WAS NOT GROUNDED.