What was found
LGA - FLT 6525 - DURNG TAXI OUT, THE CREW NOTICED SMOKE IN THE COCKPIT AND EVACUATED THE AIRCRAFT ON THE TAXIWAY. MAINTENANCE PERSONNEL INSPECTED THE AIRCRAFT AND FOUND THE MULTI-FUNCTION DISPLAY UNIT TO BE AT FAULT. THE SYSTEM HAD PREVIOUSLY BEEN MEL'D. MAINTENANCE REPLACED THE MULTI-FUNCTION DISPLAY UNIT, PERFORMED REQUIRED OPERATIONAL CHECKS, AND RETURNED THE AIRCRAFT TO SERVICE. (M)