As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
APU STARTS NORMALLY BUT WILL NOT POWER MAIN BUSSES. REPLACED APU GENERATOR PER MM 49 41 21, NO HELP. FOUND BAD S16 SWITCH AT P28 PANEL PER FIM TASK 24 21 00 810 820. REPLACED APU REMOTE FIRE SWITCH PER CHAPTER 20 STANDARD PRACTICES. TESTED APU AC GENERATION SYSTEM PER M/M 24 21 00. OPS CHECK GOOD.