Welcome to the Router Forums.
Is this a new machine or a used machine you bought from someone?
Are you using the original control box or is this a completely new control system?
Was this CNC running before?
We will need more information and pictures to see what you have.
We need good pictures of connections to the drivers and control card.
The problem might be in the Mach3 setup but from your description, it sounds like you might have an intermittent problem like something to do with system grounding.
Is this a new machine or a used machine you bought from someone?
Are you using the original control box or is this a completely new control system?
Was this CNC running before?
We will need more information and pictures to see what you have.
We need good pictures of connections to the drivers and control card.
The problem might be in the Mach3 setup but from your description, it sounds like you might have an intermittent problem like something to do with system grounding.
