As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: FLIGHT ATTENDANT REPORT A BURNING ELECTRICAL SMELL THROUGHOUT THE ENTIRE CABIN AT THE GATE DURING BOARDING. MAINTENANCE DETERMINED THE APU STARTER CONVERTER UNIT IN THE E&E BAY HAD A BURNT ELECTRICAL SMELL AND REPLACED IT PER AMM 49-41--61. A SATISFACTORY OPERATIONAL CHECK WAS ACCOMPLISHED WITH NO FURTHER ODORS NOTED.