As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: VENT EXTRACT FAULT, ELECTRICAL BURNING SMELL AND FUMES IN COCKPIT. NO SMOKE WAS VISIBLE. OXYGEN MASKS USED FOR 20 MINUTES WHILE TROUBLESHOOTING PERFORMED AND ALLOWED FOR FUMES TO CLEAR. NO COMPLAINTS FROM MAIN CABIN. NR 1 FLIGHT ATTENDANT REPORTED SLIGHT SMELL FOR A FEW MINUTES. MAINTENANCE REPLACED BLOWER EXTRACT FAN 18HQ PER AMM 21-26-51 AND AVIONICS FILTER AMM 21-26-43. MAINTENANCE ALSO PERFORMED SATISFACTORY OPERATIONAL CHECK PER AMM 21-26-00-710-001A.