As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(AUS) APU STARTER-GENERATOR BRUSH COVER INSULATION NOT FITTED DURING OVERHAUL. BRUSH LEADS SHORTED TO FRAME AND CAUSED DAMAGE TO THE TEST BENCH LOAD RESISTOR. STARTER-GENERATOR HAD BEEN RETURNED FROM OVERHAUL AND WAS UNDERGOING BEDDING IN ON THE TEST RIG BEFORE FITMENT. PERSONNEL/MAINTENANCE ERROR.