As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING SCHEDULED HEAVY CHECK EPSU BATTERY 10WL FWD L FAILED EMER TEST. AIRCRAFT WAS NOT GROUNDED AS A RESULT OF THE SDR REPORTABLE EVENT. REMOVED AND REPLACED EPSU BATTERY 10WL FWD L IAW AMM 33-51-38-000-002-A/33-51-38-400-002-A. OPS CHECK GOOD. AIRCRAFT WAS RETURNED TO SERVICE.