Problem with INTRA dental unit

I have a Planmeca INTRA dental unit with a technical problem I have the user, installation and parts manuals
none of these have information relevant to the problem
I am experiencing.

The unit appears to be functioning no error codes, control
panel reacts as expected except the unit fails to emit Xrays
when the expose button is pressed. The generator fails
to provide the high frequency high voltage drive to the
head. all fuses are intact the drive bridge has high voltage
green HV LED is illuminated, LED D9 illuminates during
expose button is activation.

I Suspect there is a communication protocol problem with
either the control panel, generator or the head. Each
component is of a different manufacture date by several
years perhaps there has been changes in the firmware.
can anyone help me solve this problem?

Thank you