As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DISCREPANCY: AIRCRAFT WAS UNDERGOING A HEAVY SERVICE CHECK DURING RON MAINTENANCE, NO FLIGHT DELAY. LP492867 ITEM #1 EPSU (11WL) FLAGGED UNIT FAULT EPSU, TEST FAILED. CORRECTIVE ACTION: REF AMM 33-51-38-000-001-A AND 33-51-38-400-001-A. REMOVED AND REPLACED EPSU (11WL) OPS TEST GOOD. /END/.