AxiDraw V3/A3 Personal Writing & Drawing Robot

Hi I recently bought an AxiDraw machine, all was working great but now the pen raising mechanism isn’t working.
it will still move the arm and draw but the pen doesn’t raise and I can’t get it to move in the control panel.

I have checked the power and the USB cable, and the little cable that goes into the side of the machine.

do you know why this may not be working properly?

all the best
Stuart