As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON FLIGHT 3801, CREW REPORTED WHILE AT THE GATE APU RUNNING AVIONICS ON A STRONG ELECTRICAL BURNING SMELL OCCURRED FOLLOWED BY EICAS 115 V AC BUS DISCONNECTED. THE AC POWER BUTTON AND STARTED CHECKLIST. SMELL (FUMES) DISAPPEARED SHORTLY THEREAFTER. AIRCRAFT REMOVED FROM SERVICE. INSPECTED INVERTER AND ELECTRICAL COMPARTMENTS, NO FAULTS OR SMOKE NOTED AND NR 8194; AIRCRAFT RETURNED TO SERVICE.