Z axis gone bad

Hi, I’ve had the cnc up for about a week - got the kits here. It seemed to work fine, but something has gone south though.
My zaxis seems to sometimes work, othertimes not. I took the stepper off and I’m just running it using manual mode in repetier. For a few minutes it will appear to work, then it starts making grinding noises, runs opposite direction, then will just stop accepting commands. I can turn it off for a while and it seems to “cool down” then I can get a few more commands in. It seems to not like the 1mm steps. (grinding sound) The 10mm steps run smoother - but sometimes in the wrong direction.
I’ve been through the basic software setup on this web site. I’ve even made some carves, but now I’m stuck on this z-axis issue.

My question is how to debug this? Is it the electronics, the software, the stepper?
X/Y seem ok.

Update: I (unplugged everything) switched the Y and Z drivers. The problem seems to stay with the stepper.
Its strange, a lot of the time it works fine, but it gets into fits where it rumbles or goes the wrong way.

It sure feels like a bad connection in the wiring - the way it comes and goes. Is it possible to take the cover off the stepper and verify the connections inside?

now swap the wires, does it follow the wires or the stepper.

Do you mean unplug the wires from the stepper? They don’t appear to be on a connector.

The wiring harness.

It can be the stepper, the harness, the driver, ramps, arduino, or control system.

I took your suggestion and was going to switch out the wiring harness when I noticed the harness was slightly loose!
I had covered the joint with black electrical tape, and the entire length in PET, but it must have worked loose.
I re-did the tape and it worked great!
Is there a better way to make this connection stay together other than black tape? The connectors seem inherently loose.

Thanks for all your help.

I use black tape as well. You can slide the female pins out pretty easy and give them a pinch if you think they are making poor contact.

I’ve done this on RC airplanes to keep connectors together.

I used on my joints of wires, thermo tubes (sorry don´t know whats the name on english). Its better than Black tape.

Its like this:
Thermo tube

Heat shrink tubing.

I love the small zip tie idea! Thanks for the pic! I had the same issue just a slightly different problem (my wire was shorted or faulty somewhere within the sleeve ‘thanks banggood’).


I’ve had a couple of issues with connectors not holding when shrinkwrapped… I think I’ll redo with zip ties and shrinkwrap. :wink: