As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING A REPOSITIONING FLIGHT FROM FLL TO ORL AFTER DEPARTURE THE CAPTAIN NOTICED SMOKE FORMING IN THE CABIN AND RETURNED TO FLL FOR AN UNEVENTFUL LANDING. MAINTENANCE INSPECTED THE AIRCRAFT AND FOUND THE EMERGENCY PRESSURIZATION VALVE TO BE DEFECTIVE. THE UNIT WAS REPLACED WITH A NEW UNIT AND THE AIRCRAFT WAS RETURNED TO SERVICE.