As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AT GATE ON APU PWR W/ PACKS RUNNING IT KICKED PWR OFF AND FAULT LT. CAME ON, WE PUT EXT PWR ON BUS. ACFT GROUNDED. REMOVED STARTER GENERATOR FILTER HSG AND FILTER ELEMENT IAW 49-91-12. NO CONTAMINATION OF FILTER ELEMENT NOTED. R & R STARTER GENERATOR OIL FILTER SWITCH IAW AMM 49-91-13. REPLACED OIL FILTER ELEMENT IAW AMM 49-91-12. LEAK CHECK OK. OPS CHECK NORMAL IAW AMM 49-11-00.