Machine digging deeper

[routerdriver]

I would begin by looking inside the controller for signs of a short or loose connection.Without knowing a bit more about the nature of the machine it isn't really possible to say more than examine all aspects of the module that controls the Z axis,including the coupling from the stepper.I would try -after removing the cutter-moving the Z axis in space to see if it does what it should.

[BruceR]

Thanks very much for helping me. I went out this morning to, as you say, check the electronics, and UCCNC would only open in demo mode so I think there’s a corruption in the PC. I’m going to get a friend to check the PC hardware, fix it, and then reinstall UCCNC. I see there is a text file on the desktop which I think is the license. I’ll need to bring the whole thing in to the house where it can reach wifi.
Many thanks again fir your help.