As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLT 3068 - DURING CRUISE BETWEEN DAY AND DTW, CREW NOTED SMOKE COMING FROM THE RT ESSENTIAL BUS CIRCUIT BREAKER PANEL. THE CREW SHUT OFF THE RT ESSENTIAL BUS AND THE AIRCRAFT RETURNED TO DAY. MAINTENANCE REPLACED THE RT ESSENTIAL BUS CIRCUIT BREAKER LIGHTING PANEL. THE SYSTEM PERFORMED SATISFACTORILY. (W)