As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING HEAVY CHECK, EPSU UNIT 12WL FAILED PTT FLAG UNIT FAULT. NOTE: THIS FAULT WAS FOUND DURING A RON MAINTENANCE VISIT AND DID NOT CAUSE A FLIGHT DELAY. REMOVED AND REPLACED EPSU UNIT (FIN 12WL) IN REF TO AMM 33-51-38-400-001-A. OPS CHECK GOOD.