What was found
AIRCRAFT CONFIGURED FOR LANDING, SPEED 150 KTS, A RUMBLE AND VIBRATION FELT BY BOTH PILOTS FOLLOWED BY PWS FAIL ON BOTH DISPLAYS. ACFT GROUNDED. PERFORMED A WEATHER RADAR SYSTEM BITEIAW FIM 34-43 TASK 801. WEATHER RADAR SYSTEM OPS TESTED IAW AMM 34-43-00-710-802-001, PWS PROBLEM IAW FIM 34-43 TASK 815. NO FAULTS NOTED OR DUPLICATED. NO VIBRATIONS FELT, OTHER THAN THE DRIVE UNIT OPERATION. R/T GVI SHOWS NO ISSUES, COOLING FAN CLEANED. DRIVE UNIT, R/T PREVIOUSLY CHANGED IAW FIM 34-43 TASK 815 STEP F (3), SUBTASK (E) FOR KNOWN PWS FAIL MESSAGES ON TAKEOFF AND APPROACH. OPS TESTED NORMAL. FOUND THE WEATHER PANEL TEST BUTTON STICKY. REMOVED AND REPLACED THE WEATHER RADAR CONTROL PANEL IAW AMM 34-43-91. OPS TESTED NORMAL.