What was found
AFTER CARGO DROP-OFF AT EIS AIRPORT PILOT RECEIVED CLEARANCE TO ENTER RUNWAY AND THEN FOR TAKEOFF. AFTER ALIGNING THE AIRCRAFT ON RUNWAY 07 PILOT PROCEEDED TO APPLY TAKEOFF POWER WHEN HE NOTICED SMOKE DEVELOPING ON THE UPPER LEFT CORNER OF THE WINDSHIELD, NEAR THE COMPASS AND MAGNETO SWITCHES. PILOT IMMEDIATELY PROCEEDED TO REDUCE POWER AND OPENED DOOR HATCH/ WINDOW TO VENTILATE CABIN. PILOT PROCEEDED TO INFORM EIS AIRPORT TOWER THAT HE WOULD BE EXITING THE RUNWAY DUE TO SMOKE IN THE COCKPIT. AFTER SMOKE CLEARED PILOT NOTICED TWO CIRCUIT BREAKERS HAD TRIPPED THESE BEING LABELED AS "CABIN LIGHTS". WITH NO SMOKE VISIBLE AND THE SITUATION UNDER CONTROL PILOT THEN FINISHED TAXIED TO RAMP AND PROCEEDED TO INFORM MAINTENANCE TEAM OF THE SITUATION. MECHANIC INSPECTED AND FOUND THE SMOKE HAD DEVELOPED DUE TO THE MAGNETIC COMPASS LIGHT CABLES MAKING CONTACT HEATING UP THE CABLES AND THEREFORE TRIPPING CIRCUIT BREAKERS ASSOCIATED WITH SYSTEM. MECHANIC PROCEEDED TO DEFER THE ITEM UNDER FAA APPROVED MEL FOR BN2A MKIII.