What was found
REJECTED TAKEOFF, 80 KNOTS, FOR RADAR FAILURE ON TAKEOFF. RADAR AUTO SWAPPING FROM OPERATIVE TO INOPERATIVE, BOTH CAPTAINS & FIRST OFFICERS SIDE. THE SYS WAS REQUIRED DUE TO THUNDERSTORMS IN THE VICINITY & EN-ROUTE. ACCOMPLISHED SATISFACTORY WX RADAR BITE IAW AMM 34-41-00-740-002A. IAW E & O 34-41-00-0001-04 RADAR CONTROL PANEL BELOW 2500', CONTROL SWITCH MUST BE IN CAPTAINS OR FIRST OFFICERS TO NOT HAVE LOSS OF WX RADAR IMAGE. WX RADAR CHECKED OK.