As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CREW NOTICED ELECTRICAL BURNING SMELL IN COCKPIT ONLY. UTILITY BUSSES AND RECIRC FANS SHUT OFF AND EQUIP COOLINGIN STDBY. SMELL DISSIPATED. CONTINUED TO ORD. AIRCRAFT RETURNED TO GATE WITH REPORT OF SMOKEY ODOR AND FWD EQUIP COOLING EXHAUST FAN C-B POPPING.