What was found
ON TAKEOFF IAS/MACH WINDOW WOULD NOT CHANGE WHEN SPEED WINDOW DIAL WAS TURNED. TRIED LEVEL CHANGE, VERTICAL SPEED, AND SPEED INTERVENTION. VNAV MODE WORKED FINE. AT APPROX. 10,000' THE IAS/MACH SELECTOR WORKED NORMALLY IN ALL MODES. ALL IAS/MACH MODES WORKED NORMAL DURING FLIGHT, APPROACH AND LANDING. ACFT GROUNDED. PERFORMED GROUND VERIFICATION OF MODE CONTROL PANEL, REF AMM 22-11-34. BITE CHECK GOOD. GROUND VERIFICATION OF MACH/AIRSPEED SELECTOR CHECKED NORMAL.