What was found
AIRCRAFT HAS BURNT ELECTRICAL SMELL THROUGHOUT COCKPIT AND CABIN. AIRCRAFT WAS AT 3500 FT MSL STARTED DECENT, SMELL GOT STRONGER. DECIDED TO LAND IN FIELD, ON THE WAY DOWN LOST STANDBY ATTITUDE INDICATOR, #3 VHF RADIO, HSI INDICATIONS ON PFD AND SYNTHETIC VISION ON PFD. UPON SHUT DOWN DISCOVERED STANDBY ATTITUDE INDICATOR CIRCUIT BREAKER POPPED. MAGNETOMETER WAS DETERMINED TO BE THE FAULT, WHICH CAUSED THE FAILURE OF THE CIRCUIT BREAKER WHICH CAUSED THE SMELL.