As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ETOPS SIGNIFICANT SYS - APPROX 45 MIN. AFTER ARRIVAL APU GEN KICKED OFF LINE WITH A BPCU FAULT OF "DP TRIP" AND "OVERLAP ZONE". T/S IAW FIM 24-20-00/101 STEP F (1) (B) 1 THRU 6. NO TROUBLE NOTED. INSPECTED PINS OF APU GCU, NO TROUBLE NOTED. REPLACED APU GCU IAW AMM 24-22-02/401. PERFORMED SEVERAL POWER SWAPS BETWEEN APU GEN AND EXT POWER. NO TROUBLE NOTED. RAN APU & LOADED GENERATOR FREQS & VOLTS, OK PWR TRANS SERVAL TIMES, OPS NORMAL.