As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WX RADAR WILL NOT DISPLAY KNOWN THUNDER STORMS IN AUTO MODE. WEAK RETURN ARE POSSIBLE IN MANUAL MODE BUT WILL NOT DISPLAY VISIBLE STORM DIMENSIONS ON RADAR DISPLAY. VARIOUS GAIN ADJUSTMENTS MADE WITH NO CHANGE AT MAX GAIN. GROUND CLUTTER FUNCTION WORKS NORMALLY. GROUNDED - YES. NO FAULTS NOTED ON MDS. C/W WEATHER RADAR SYSTEM TEST = NO FAULTS NOTED DURING TEST, TESTS OK. REF B737-9 AMM 34-41-00-730-801.