# Z axis acting up
**URL:** https://forum.sienci.com/t/z-axis-acting-up/27157
**Category:** ❓ Question
**Created:** [September 24, 2026, 8:48pm UTC](https://forum.sienci.com/t/z-axis-acting-up/27157 "2026-09-24T20:48:15Z")
**Posts on this page:** 8
**Page:** 1
### Author:  [@Bergees](https://forum.sienci.com/u/Bergees)
#### Post date: [September 24, 2026, 8:48pm UTC](https://forum.sienci.com/t/z-axis-acting-up/27157/1 "2026-09-24T20:48:15Z")
Working with Longmill MK2 . I had to replace the stepper motor on the Z axis. Now when I use the control panel for the up-and-down motions, it will only go down not up when it gets right to the bottom it stalls and I have to reboot G Center, and when it gets all the way to the top it stops and then starts going down. Has something in my settings changed when I replaced the stepper motor.
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### Author:  [@gwilki](https://forum.sienci.com/u/gwilki)
#### Post date: [September 24, 2026, 11:17pm UTC](https://forum.sienci.com/t/z-axis-acting-up/27157/2 "2026-09-24T23:17:27Z")
@Bergees I changed the title. You posted “A axis”. 😀
Where did you source the new motor?
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### Author:  [@Bergees](https://forum.sienci.com/u/Bergees)
#### Post date: [September 24, 2026, 11:45pm UTC](https://forum.sienci.com/t/z-axis-acting-up/27157/3 "2026-09-24T23:45:21Z")
Picked it up yesterday from Sienci in Waterloo
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### Author:  [@gwilki](https://forum.sienci.com/u/gwilki)
#### Post date: [September 25, 2026, 12:11am UTC](https://forum.sienci.com/t/z-axis-acting-up/27157/4 "2026-09-25T00:11:22Z")
@Thanks. With respect, your post is somewhat contradictory. First you say that “it will only go down not up”. Then you say that “when it gets all the way to the top”. So, clearly, it will go up.
Can you better describe what it is actually doing? In the meantime, you may want to check the dip switches on the motor.
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### Author:  [@Bergees](https://forum.sienci.com/u/Bergees)
#### Post date: [September 25, 2026, 1:06am UTC](https://forum.sienci.com/t/z-axis-acting-up/27157/5 "2026-09-25T01:06:13Z")
This happened before i replaced the Stepper motor. The stepper motor seized which is why I replaced it. Yes, it is confusing. Once the spindle goes all the way down, I have to restart gSender to get it to go up again When it gets to the top, it starts to go back down again. When I press the up arrow it still continues all the way down and I have to reboot gsender to get it to go up. Where are the dip switches and what are their settings?
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### Author:  [@Jens](https://forum.sienci.com/u/Jens)
#### Post date: [September 25, 2026, 5:53am UTC](https://forum.sienci.com/t/z-axis-acting-up/27157/6 "2026-09-25T05:53:03Z")
Isn’t the Longmill MK2 a mill with open loop steppers? If so, there are no dip switches.
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### Author:  [@Bergees](https://forum.sienci.com/u/Bergees)
#### Post date: [September 25, 2026, 10:12am UTC](https://forum.sienci.com/t/z-axis-acting-up/27157/7 "2026-09-25T10:12:53Z")
Indeed. You are correct.
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### Author:  [@gwilki](https://forum.sienci.com/u/gwilki)
#### Post date: [September 25, 2026, 10:57am UTC](https://forum.sienci.com/t/z-axis-acting-up/27157/8 "2026-09-25T10:57:06Z")
@Bergees @Jens Sorry about that. I know that my Mk1 doesn’t, except for the Vortex, but for some strange reason, I was confused about the Mk2.
At the risk of putting my foot in it again, it sounds like the motor may be bad. However, I would suggest that you open a support ticket so that Sienci can prove me wrong.