What was found
PILOT REPORTED ELECTRICAL SMELL IN COCKPIT, NO VISIBLE SMOKE. HE DECLARED AN EMERGENCY AND PROCEEDED TO ISOLATE, ELECTRICAL SYSTEMS. LANDING WAS UNEVENTFUL. MAINTENANCE INSPECTED THE AIRCRAFT WIRING, CIRCUIT BREAKERS, AND SWITCHES AND COULD FIND NO DISCREPANCIES. THE NR 2 TRANSPONDER WAS FOUND TO BE INOPERATIVE. THE FAULTY TRANSPONDER WAS REPLACED AND CERTIFIED. THE AIRCRAFT WAS TEST FLOWN WITH NO DISCREPANCIES NOTED. THE AIRCRAFT IS RETURNED TO SERVICE.