As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING THE EEP CHECK THE APU GEN VOLTS & FREQS SHOWING 0 FREQS AND 2 VOLTS. DIVERSION TIME 121 MINUTES. VERIFIED DISCREPANCY. PERFORMED APU AND GCU BITE. NO FAULTS NOTED. REMOVED AND REPLACED APU START CONVERTER PER AMM 49 41 61. OPS NORMAL. APU GEN BUS OFF BLUE LIGHT IS ON AND P5 13 ELEC METERS PANEL SHOWS PROPER VOLTAGE AND FREQS WHEN APU IS READY TO SUPPLY POWER.