As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT IN BASE MAINTENANCE: DURING OPERATIONAL TEST OF EPSU OPERATIONAL OF EMERGENCY POWER SUPPLY UNITS BITE CHECK EPSU 10WL DONT PASS TEST AT FWD GALLEY AREA. MAINTENANCE REPLACED EMERGENCY POWER SUPPLY (EPSU) FIN 10WL AT FWD GALLEY AREA IAW AMM 33-51-38-400-001-A.