As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DUAL TRANSPONDER FAILURE IN HEAVY PRECIPITATION. NO FAILURE INDICATION ON SPZ8000 SYSTEM. CENTER REQUESTED RESET OF TRANSPONDER, AND DIRECTED OUT OF RVSM AIRSPACE WHEN UNSUCCESSFUL. HANGAR TESTS OF POWER OUTPUT SHOWED 40WATTS BEFORE CABLES REPLACED, AND 400 WATTS AFTER.