As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING EPSU BITE TEST POST BATTERY CHANGE, FOUND 12WL EPSU WITH 335138 EPSU(12WL)EMER R/DEU-B(300RH6) FAULT. / TROUBLESHOT 335138 EPSU(12WL)EMER R/ DEU-B(300RH6). REMOVED AND REPLACED 12WL EPSU IAW AMM 33-51-38-400-001-A. EPSU OPS TEST GOOD."