As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CREW EXPERIENCE SMOKE IN THE COCKPIT EN ROUTE FROM MKL-ATL AND DIVERTED TO M29 IN CLIFTON, TN. UPON INSPECTION BY MAINTENANCE PERSONNEL IT WAS DISCOVERED THAT THE SOURCE OF THE SMOKE WAS FROM AN INTERNAL SHORT IN THE GARMIN GNS 530 THE SYSTEM WAS PLACED ON MEL AND REPOSITIONED TO MEM WHERE THE GNS 530 WAS REPLACED