What was found
ON DESCENT, TURNED WEATHER RADAR ON, WX FAIL APPEARED ON MFD. TURNED OFF THEN ON RECEIVED WEATHER RADAR FAIL & NO PWS, TURNED OFF AND AS EXPECTED NO PWS REAPPEARED BELOW 1600. ACFT GROUNDED. ACCOMPLISHED GVI OF WEATHER RADAR TRANSCEIVER, FOUND TO COVERED IN DUST. REMOVED WEATHER RADAR TRANSCEIVER. VACUUMED DUST . VERIFIED BLOWER OPS NORMAL. INSTALLED ORIGINAL TRANSCEIVER, ACCOMPLISHED OPS TEST, TEST PASSES. REF MM 34-43-00-710-802-001 & 34-43-41-400-801.