As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
APU GENERATOR WOULD NOT COME ONLINE DURING TAXI. APU FIELD TRIPS, BPCU APU BIT:OPEN POR-FDR GEN AND UNDERVOLT TRIP. TRIED APU GCU, NO HELP, RE-INSTALLED ORIGINAL. REPLACED APU GEN SWITCH, NO HELP. REMOVED AND REPLACED APU GENERATOR PER MM. LEAK AND OPS CHECKED GOOD.