What was found
FLT NR 4743 - PSM - AFTER TAKEOFF, THE AIRCRAFT ROLLED TO THE LEFT REQUIRING STANDBY TRIM TO MAINTAIN STRAIGHT AND LEVEL FLT. THE AIRCRAFT DIVERTED TO MHT LANDING WITHOUT INCIDENT. MAINTENANCE WAS DISPATCHED TO THE AIRCRAFT AND RERIGGED THE MAIN ROLL TURN TAB IAW THE SAAB MM AND RETURNED TO SERVICE. THE ROLL TRIM SYSTEM HAD BEEN ON MEL AND 'M' FUNCTION PROCEDURES OF THE MEL HAD NOT BEEN CORRECTED. (M)