What was found
WEATHER RADAR FAILED ON PRE FLIGHT. REPLACED WEATHER RADAR TRANSCEIVER. OPS CHECKED GOOD. BITE TEST FAILURE MESSAGE WAS "RT". NOTED SEVERAL RECENT HISTORIES WITH TRANSCEIVER AND CONTROL PANEL REPLACED. TRANSCEIVER BOX WAS VERY WARM. SUSPECT COOLING FAN IN TRAY MAY BE INOP.ERATIVE. REMOVED WEATHER RADAR TRANSCEIVER IN ORDER TO INVESTIGATE LOG 1 (LACK OF COOLING IN E&E). FOUND NO AIR FLOW FROM MOUNTING TRAY. REINSTALLED WEATHER RADAR TRANSCEIVER AND CHECKED FOR FAN OPERATION, NO JOY. . REPLACED THE WEATHER TRANCEIVER COOLING FAN. FAN OPERATION CHECKED GOOD. ACCOMPLISHED OPERATIONAL TEST AND BITE TEST AT TRANCEIVER UNIT. TESTED OK.