What was found
RADAR IN TURB MODE GOES FROM 0 TO +2.5, CAPTAINS SCREEN WOBBLES 80NM SCALE & BELOW AND WITHIN 30 NM OF LEVEL 4 DID NOT PAINT PRECIPITATION. AIR RETURN TO MSP. MAINTENANCE REPLACED RADAR DISP AND R/T. R/T P/N ON&OFF 204-1217-0414, S/N ON 7203, S/N OFF 7462, DISPLAY P/N ON&OFF 2041222-0435, S/N ON 4699, S/N OFF 5000. WX RADAR SYSTEM TEST GOOD IAW RJ MM CHAPT 34.