What was found
OPERATIONAL CHECK OF THE EMERGENCY POWER SUPPLY UNITS BY BITE-CHECK EMERGENCY LIGHTS FAIL TEST AT CIDS PANEL. FAULT EPSU INT LOAD FWD L ATA 33-51-38. CYCLED BREAKERS NO HELP. REMOVED CEILING PANEL AT DOOR 1 LEFT. DID TEST OF LIGHTING BOX FAULTING INTERIOR LIGHTS. FOUND EVERY LIGHT THAT IS CONTROLLED BY THE FWD EMERGENCY LIGHT POWER SUPPLY TO BE WORKING PROPERLY BUT FAULT CODE IS STILL PRESENT DURING THE TEST. REMOVED AND REPLACED THE FWD ESPU (10WL) IAW AMM TASK 33-51-38-000-001-A AND TASK 33-51-38-400-001-A. TRANSFERRED THE BATTERY TO THE NEW ESPU. OPS CHECKS GOOD. NO FAULTS.