Andy, thanks for your response.

I have a closing the circuit on contact type. That kind of behaviour was occuring when running gcode. the router would go drive to plunging point and start drilling down the piece.
Would that still be characteristic of a dodgy zero plate wire? I will have a look when get to workshop though.

Any idea why the manual operation of xyz controls is not available all over sudden? I did check all the wiring or stepper drive and main board, all as should be. Can't see any visual
problems.

thanks