As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
EN ROUTE TO ATL FROM SJU, NR 1 RADAR INDICATES NO RETURN WITH LARGE SPIKE DOWN MIDDLE OF DISPLAY. NR 2 RADAR CONSTANTLY SHOWS TEST PATTERN AT ANY SETTING. FLIGHT DIVERTED TO MIA WITHOUT INCIDENT. MAINTENANCE CHANGED RADAR ANTENNA AND SYSTEMS OPS CHECK NORMAL PER M.M. 34-41-1.