During the power on phase, the local control board of the keyboard is
controlling that during power on no more than 1 button is pressed.
Only the case of column up/column down is allowed and used to enter
the set up procedure, so if this procedure is started without an explicit
request, it means that those buttons are pressed.
In this case, replace the keyboard membrane and after the control board.
Otherwise the following message is displayed:

Release the corresponding key if pressed and repeat the power on
procedure. Otherwise replace the keyboard membrane and after the
control board A4.