Z axis issues

My machine has run smooth for over a month now. Last week my Z Axis is acting weird. Using Easel , if I press up 10 times, it will do UP , UP , UP , DOWN , UP , DOWN, DOWN ETC. It is random every few presses of the arrow. Any ideas what could be causing that?

I have reboot the machine, PC and cleared my cache. Any other ideas?

That is weird one. Hopefully someone can help you out.

Check the electrical connections at the terminal block on the back, and check that the g-shield is tightly seated on the arduino.

It sounds like you’re getting a short between 2 of the wires on the z axis. Also check that the green terminal blocks on the g-shield are in good shape and not loose.