As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
INSPECTION TYPE:N/A APU QUIT AND WOULDN'T ACCEPT GROUND POWER. SMELL OF ELECTRICAL FUMES IN COCKPIT. MX STARTED THE APU, PERFORMED EPCU RTS AND FUMES WERE FROM THE NR 3 PACK. PERFORMED EPCU RTS ALL PASS. INSPECTED CTR ACCESSORY AND FWD E&E NO PROBLEMS NOTED, FUMES OR SMELL FROM NR 3 PACK. WARM STARTED APU. ALL CHECKS OK.