As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DISCREPANCY: FAULT WAS DISCOVERED DURING SCHEDULED RON MAINTENANCE AND CAUSED NO FLIGHT DELAY OR CANCELLATION. LP500063 ITEM #3 EPSU BATTERY AT POS 13WL FAILED OPS TEST. CORRECTIVE ACTION: REMOVED AND REPLACED EPSU AT POSITION 13WL. REF AMM 33-51-38-000-001-A AND AMM 33-51-38-400-001-A. OPS CHECKED GOOD. /END/.