As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT IN BASE MAINTENANCE: CABIN INTERCOMMUNICATION DATA SYSTEM 1 IS PROVIDING NO DATA TO CENTRAL FAULT DISPLAY INTERFACE UNIT DETECTED BY GROUND SCAN OF CENTRAL FAULT DISPLAY INTERFACE UNIT. REMOVED AND REPLACED EMERGENCY POWER SUPPLY UNIT (AALA202110044789) BY FORWARD ENTRY DOOR PER AMM 3351-38. REMOVED AND REPLACED EMERGENCY POWER SUPPLY UNIT BELOW LEFT EMERGENCY DOOR PER AMM 33-51-38.