As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
JFK - INFLIGHT RDU-LHR. CREW REPORTED ONE AIR TRAFFIC CONTROLLER TRANSPONDER WAS ALREADY ON MEL WHEN 2ND ATC TRANSPONDER FAILED. FLIGHT DIVERTED, LANDED WITHOUT INCIDENT. REPLACED ATC CONTROL PANEL AND BOTH ATC TRANSPONDERS (MPN 066011271602). SYSTEM GROUND CHECK NORMAL OPERATION.