As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
RADAR HAS INTERMITTENT VERY LOW POWER OUT DURING FLIGHT. POOR DEPICTION OF HAZARDOUS THUNDERSTORMS WITH GAIN HIGH OR LOW. TESTS OK ON GROUND. UNSATISIFACTORY FOR FLIGHT INTO WEATHER WITH POSSIBILITY OF NEED FOR RADAR. POOR RECEPTION OF DATA DEPICTING SEVERE THUNDERSTORMS. GROUNDED - YES. DUE TO HISTORY REMOVED & REPLACED WXR RECEIVER/TRANSMITTER PULLED & RESET 2 ASSOCIATED CBS. B737-900 AMM 34-43-121 ACCOMPLISHED OPS CHECK AMM 34-43-00.