As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ORD - FLT 4164 - CAPTAIN NOTED, AFTER POWERING UP A/C, SMOKE WAS COMING FROM QUADRANT AND STRONG SMOKE SMELL WAS IN CABIN AND COCKPIT. MX INSPECTED AND FOUND AVIONICS VENT FAN BURNED. RAI FAN IAW JIC 21-23-21. PERFORMED OPERATIONAL CHECK SATISFACTORILY AND RETURNED A/C TO SERVICE. (M)