What was found
EMERGENCY PWR ON ALERT INFLIGHT. WHEN SELECTED OFF, DC3 DID NOT APPEAR POWERED. EMERGENCY PWR ARM AND ALERT STAYED ON. ADG DEPLOYED. ON SHORT FINAL DC3 UNPOWERED WITH LOSS OF ADG POWER RESULTING IN LOSS OF ASSOCIATED SYSTEMS. FLIGHT DIVERTED DFW AND LANDED WITHOUT INCIDENT. INTEREGATED EPCU FOUND TR-3/INTFC FAULT. WORK ACCOMPLISHED PER AMM &TSM 24-30-00/24-31-01-2. REMOVED & REPLACED NR 3 TR PER AMM 24-31-01. ACFT RELEASED FOR SERVICE.