As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLT BX742 FROM TOL TO OMA. NR 1 IN LINE FOR TAKEOFF, NR 1 GENERATOR HAD A 3 LIGHT TRIP WITH A BRIEF LOSS OF NR 2 & 3 GCB''S AND ESSENTIAL POWER (SELECTED ON NR 3 AT THE TIME). CREW REPORTED SMELLING SMOKE IN THE COCKPIT. AIRCRAFT RETURNED TO BLOCKS WITHOUT INCIDENT. FOUND WATER FROM HEAVY RAIN IN THE NR 1 GENERATOR CONTROL UNIT (GCU). REPLACED GCU. OPS CHECK GOOD. AIRCRAFT RETURNED TO SERVICE.