What was found
(CAN) THE CREW SMELLED SMOKE IN THE COCKPIT AND RETURNED TO THE AIRPORT JUST AFTER TAKEOFF. THEY HAD SEVERAL CIRCUIT BREAKER TRIPPED FOR THE DC BUS 1 ON THE EMSCDU AND EVENTUALLY THE DC BUSS 1 FEED 4, WHICH FEED SPDA 4 TRIPPED AS WELL. SEVERAL ANOMALIES WERE NOTED IN THE COCKPIT, SUCH AS LIGHTS AND SOME AVS EQUIPMENT GOING OFF. UPON INSPECTION, THE P1 CONNECTOR WAS FOUND BURNED ON SPDA 4. THE CONNECTOR SEEMED TO BE WELDED TO THE SPDA. THE SPDA WAS REMOVED WITH THE CONNECTOR STILL ATTACHED. A NEW SPDA AND P1 WERE INSTALLED AND THE AIRCRAFT RETURNED TO SERVICE.