What was found
(CAN) THE AIRCRAFT HAD BEEN RUNNING FOR 2-3 MINUTES WHEN THE CREW COULD SMELL AND SEE SMOKE. MAINTENANCE FOUND THE SOURCE OF SMOKE CAME FROM THE VENT BLOWER. FURTHER INVESTIGATION FOUND THE POSITIVE BRUSH HOLD DOWN SPRING TO SHORTING OUT TO THE CASE CAUSING THE SPRING TO WELD ONTO IT. MAINTENANCE ALSO FOUND THE CLEARANCE BETWEEN THE NEGATIVE BRUSH HOLD DOWN SPRING AND THE CASE TO BE MINIMAL. THIS CONCERN WAS FORWARDED TO BEECHCRAFT AND THE MANUFACTURER OF THE VENT BLOWER (ELECTRO MECH). A REPORT WAS ALSO SENT TO TRANSPORT SAFETY BOARD.