As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
APU GENERATOR WILL NOT COME ONLINE. SHOWS NO FREQUENCIES OR VOLTS. ACFT GROUNDED. REMOVED AND REPLACED APU GCU IAW AMM 24-21-81/401. APU GCU BITE TEST PASSED. APU AC GEN AND CONTROL SYSTEM OPS TESTED NORMAL IAW AMM TASK 24-21-00-700-803.