What was found
AFTER TAKEOFF TOL, SMOKE EMANATED FROM FLIGHT ENGINEER'S PANEL IN THE VICINITY OF THE CABIN PRESSURE CONTROLLER AND THE HYDRAULIC SELECTOR CONSOLE. FLIGHT RETURNED TO TOL FOR AN UNEVENTFUL LANDING. MAINTENANCE FOUND THAT THE F/E'S INSTRUMENT WHITE LIGHTING BALLAST HAD FAILED. THE BALLAST WAS REPLACED, THE AREA INVESTIGATED FOR ANY OTHER FAULTS AND THE AIRCRAFT WAS RETURNED TO SERVICE.