What was found
DURING HEAVY MAINTENANCE: FAULT EPSU EMERGENCY POWER SUPPLY UNIT SHOWED MESSAGE BAT/EPSU 10WL,11WL, AND 15WL IN THE PASSENGER CABIN; REF AEROMAN NR 2022-218602 WO 2022 117/1REMOVED AND REPLACED SERVICEABLE BATTERY EPSU IN POSITION 10WL P/N: 3214-31 S/N: 863257 AT FWD GALLEY AREA, 11WL P/N: 3214-31 S/N: 885500 AFT LH MID-CABIN AND 15WL P/N: 3214-31 S/N: 873375 FWD LH MID CABIN IAW AMM 33-51-38-000-002-A AND AMM 33-51-38-400-002-A . PERFORMED OPERATIONAL TEST IAW AMM 33-51-00-710-001. THE TEST IS OK.