As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) FLIGHT CREW REPORTED THAT THE BETA WARNING SOUNDED AT APPROX FL40, AT 1200 RMP AND C/L AT MAX. CONTINUOUS. AIRCRAFT RETURNED TO DEPARTURE AIRPORT. MAINTENANCE ACTION, BETA WARNING MICRO SWITCH ACTUATOR REPLACED, ADJUSTED, AND TESTED SERVICEABLE AS PER AMM 31-51-02.