What was found
ELECTRICAL BURNING ODOR DETECTED AND SMOKE NOTED IN CABIN JUST PRIOR TO TAKE-OFF. TAKE-OFF ABORTED. MAINTENANCE INSPECTED THE AIRCRAFT FOR ANY OBVIOUS SIGNS OF BURNING OR SMOKE DAMAGE, NONE NOTED. FLIGHT CREW INITIATED A FUNCTIONAL START-UP TO DETERMINE SOURCE OF DISCREPANCY. DISCREPANCY NOTED IN NR 2 EMS VACUUM PUMP. DAMAGE LIMITED TO INTERNAL COMPONENT OF VACUUM PUMP WITH NO FURTHER DAMAGE TO WIRING, OR SYSTEMS. MAINTENANCE REPLACED THE NR 2 VACUUM PUMP. POST MAINTENANCE FUNCTIONAL CHECKS REVEALED NO FURTHER DISCREPANCIES. AIRCRAFT RETURNED TO SERVICE.