As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIR RETURN - PILOTS REPORTED THE CAPTAINS EHSI WENT OUT FOLLOWED BY SMOKE IN THE COCKPIT. TURNING THE PILOTS SIDE SCREENS OFF STOPPED THE SMOKE. IT APPEARED TO THE PILOTS THAT THE CAPTAINS SIDE MIC (HEADSET) WAS LOSING IT'S EFFECTIVENESS AS WELL. OPEN