As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CRUISE AT FL380, VIBRATION FELT IN FLOOR, COCKPIT & GALLEY FLOOR. FOLLOWED BY A BURNING SMELL IN COCKPIT & CABIN. AFT FLIGHT ATTENDANT REPORTED SEEING HAZE IN THE REAR CABIN. DECLARED EMER DUE TO HEAVY ELEC FUMES & VIBRATION. REPLACED AVEC EXTRACT FAN. TESTED GOOD IAW AMM 21-26-51.