Not a problem I remember seeing mentioned by other owners.? Most of the push buttons on the display head are set up in groups of four in series with resistors in between them.? When a button is pushed it grounds the series resistor chain, which determines the voltage that is read by an A/D input on the CPU, which deterrmines which button was pushed, that causes a control message to be sent to the main CPU.? If all of the other buttons seem to work, then there is either a problem with the CPU A/D input signal (pin 79, K1IL for the Fn switches), the pullup resistor to 3.3 VDC for? K1IL (R2017) or one of the series resistors between the switches.
A service manual and an ohmmeter can verify the resistors, PCB trace and switches are OK.? If so, then it may be a problem with the Display's CPU or the solder joint of pin 79.?
Steve, W3AHL
Steve W3AHL