As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
NR 2 BUS TIE RELAY FAILED CAUSING LOSS OF NR 2 GENERATOR BUS DURING FLIGHT RESULTING IN AN AIR TURNBACK TO WMKK. MAINTENANCE REMOVED AND REPLACED NR 2 BUS TIE RELAY AND THE ELECTRICAL POWER CONTROL UNIT. OPERATIONAL CHECKS OF THE SYSTEM CHECKED OK. (M)