BONANZA DECLARES EMER WHEN ELECTRICAL SMOKE FILLS COCKPIT.

Narrative

9 MI SSE OF DEC; I NOTICED A FAINT ODOR. I PROCEEDED TO CHK THE HEATING SYS IN THE COCKPIT; NOTING IT WAS OFF; NEXT LOOKED AT THE AMMETER AND VOLTMETER INDICATIONS; WHICH WERE NOT IN THE NORM. I THEN TURNED THE FOLLOWING ELECTRICAL LOADS OFF: ANTICOLLISION LIGHTS; RADIO MASTER SWITCH; GENERATOR/ALTERNATOR SWITCH; AND BATTERY MASTER SWITCH. AFTER EVERYTHING WAS PROMPTLY TURNED OFF IT WAS NOTICED SOME ELECTRICAL EQUIP WAS STILL BEING PWRED (WHICH IS BELIEVED TO BE CAUSED BY A RUNAWAY GENERATOR/ALTERNATOR WHICH CREATED A SHORT TO GND). THESE SYS INCLUDED AN AMMETER/VOLTMETER WHICH IS ON THE BATTERY BUS; TURN COORDINATOR; #2 COM; FUEL GAUGES; AND THE LIGHT ON THE NOSE GEAR POS INDICATOR (ALL OF WHICH ARE MASTER SWITCH DEPENDENT). INSTS STARTED TO SMOKE AND POP. AT THIS TIME I CALLED DEC TWR APPROX 6 NM SSE ON MY HAND- HELD TRANSCEIVER. I INFORMED THEM OF MY SIT AND EXPRESSED MY INTENTION TO LAND IMMEDIATELY. BY THIS TIME THE CABIN WAS STARTING TO FILL WITH SMOKE. SMOKE WAS COMING FROM THE FUEL GAUGES THAT NOW APPEAR TO BE BURNT; THE TURN COORDINATOR AND #2 COM. I NEXT PROCEEDED TO PULL THE LNDG GEAR EXTENSION CIRCUIT BREAKER; PLACED THE GEAR LEVER IN THE DOWN POS AND CRANK THE GEAR DOWN 50 TURNS. SOMEWHERE IN THIS CONGESTION; THE EMER WAS DECLARED. BEFORE LNDG; A LOW PASS WAS INITIATED TO ENSURE THE GEAR WAS DOWN. I FINALLY PROCEEDED TO MAKE A SAFE LNDG ON RWY 18 AT DEC. BY THIS TIME THE SMOKE HAD SUBSIDED. ONCE ON THE GND AND OUT OF THE AIRPLANE; I DISCONNECTED THE BATTERY AND LOOKED OVER THE ACFT FOR ANY OTHER DAMAGE.