When trying out the GRBLpanel tutorial I encountered a problem with the Z-axis gantry getting stuck. When jogging it would seize with the screw not turning. Jogging it back and forward again would enable it to move past the point seized.

Adding silicone lubricant to the guiderods seems to have helped a little but it is still getting stuck with the motor making an awful noise. There seems to also appear black powder (guessing the core material of the boards) on top of the gantry when this happens, so I'm wondering if the plastic bit on top of the lead screw is getting stuck in its hole.

Any suggestions for fixing the issue? Also, how would one go about in replacing the Z-axis motor if/when it'll need replacing?

Thanks.