As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PTY - FLT 622 - DURING CRUISE, COCKPIT CREW OBSERVED SMOKE COMING FROM THE FLIGHT CONTROL UNIT. AIRCRAFT RETURNED TO PANAMA STATION FOR MAINTENANCE. AFTER AN UNEVENTFUL LANDING AT PTY STATION, MAINTENANCE TECHS PERFORMED AN INSPECTION OF THE FCU SYSTEM, THE FCU WAS FOUND WITH A SHORT CIRCUIT. THE AIRCRAFT REMAINED ON GROUND FOR THE REPLACEMENT OF THE UNIT. (X)