As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: WHILE MAINTENANCE WAS PERFORMING AVIONICS VENTS RESETS, STRONG BURNING ELECTRICAL SMELL IN FLIGHT DECK. FOUND SOURCE OF ODOR TO BE AVIONICS FANS OVERHEATING DUE TO SKIN AIR VALVES NOT OPENING. INTERROGATED MCDU AND FOUND SKIN AIR OUTLET V (22HQ) AND SKIN AIR INLET V (15HQ) FAULTS. FOLLOWED TSM 21-26-00-810-829-A. FOUND IN AB/4A ON AEVC DAMAGED. REPLACED AEVC IAW AMM 21-26-34.