As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
BOS- AIR TURNBACK - FLT 442 - AFTER TAKEOFF FROM BOS EN ROUTE TO PHX THE CREW GOT A TRANSFORMER RECTIFIER 1 (TR1) FAILURE INDICATION AND RETURNED TO BOS. IN BOS MAINTENANCE TROUBLESHOT AND REPLACED TR1 PER AMM 24-32-51-401. THE SYSTEM OPERATIONALLY CHECKED NORMAL PER AMM 24-23-00-501. NO FURTHER DISCREPANCIES HAVE BEEN REPORTED.