As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
MACH AIRSPEED INDICATOR FAILURE. FIRST OFFICER MACH AIRSPEED FLAG IN VIEW AND INDICATOR FROZE AT 170KTS ON TAKEOFF, REMAINED THAT WAY FOR APPROX 10 SEC. A TAP TO THE CASE RETURNED TO NORMAL. REPLACED FIRST OFFICER MACH AIRSPEED INDICATOR. SHOP FINDINGS, COMPONENT SENT TO THE MANUFACTURER IN WARRANTY. SECOND SHOP VISIT OF THIS UNIT, FAULT CONFIRMED, COUNTER BINDING, REPLACED THE DRIVER MOTOR.