As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
THE PILOT OBSERVED A CARGO COMPARTMENT SMOKE WARNING LIGHT IN THE COCKPIT SHORTLY AFTER TAKEOFF FROM PBG EN ROUTE TO BUF. THE PILOT RETURNED TO PBG AND LANDED WITHOUT INCIDENT. AN EMERGENCY WAS NOT DECLARED. THE PILOT REPORTED AFTER LANDING THAT THERE DID NOT APPEAR TO BE ANY EVIDENCE OF A FIRE. MAINTENANCE AT PBG WAS ABLE TO DEMONSTRATE ON THE GROUND THAT THE WARNING WAS FALSE. A FAULTY SMOKE DETECTOR WAS REPLACED AND THE AIRCRAFT RETURNED TO SERVICE.