What was found
DURING TAXI FOR TAKEOFF, FLIGHT CREW WAS UNABLE TO START NR 1 ENGINE ON B-IGNITION. FLIGHT CREW ELECTED TO RETURN TO GATE FOR MAINTENANCE. AIRCRAFT RETURNED TO GATE WITHOUT FURTHER INCIDENT. MAINTENANCE PERSONNEL REPLACED THE NR 1 ENGINE B-IGNITION EXCITER BOX. THIS DID NOT CORRECT MALFUNCTION. DEFERRED MALFUNCTION PER MEL 74-1. AIRCRAFT RETURNED TO SERIVCE. WILL PROVIDE FOLLOW-UP REPORT WHEN CORRECTIVE ACTION IS ACCOMPLISHED. (X)