Prusa MK3S Z axis not moving down past center (see video)
 
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[Solved] Prusa MK3S Z axis not moving down past center (see video)  

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chewie
(@chewie-2)
Member
Prusa MK3S Z axis not moving down past center (see video)

Hi all, I’m struggling to fix this issue and would appreciate any guidance. Since replacing the Pi Zero with a Pi Zero 2, I’ve been having problems calibrating the Z-axis. Even with the unit powered off and manually rotating both lead screws at the same time, the Z-axis will not move down past the midpoint.

https://storage.googleapis.com/prusa3d-content-prod-14e8-wordpress-forum-prod/2025/12/67e542fd-prusa-mk3s-z-axis-not-moving-down-past-center.mp4

Printer model & firmware: Prusa MK3S (latest firmware)
Filament type & brand: issue occurs before printing, but mainly pring PETG
Slicer & version: PrusaSlicer (current version)
Print settings: Defaults (no changes). I have also performed a factory reset

What I’ve tried: Powering the unit off and manually rotating both Z lead screws in unison; no visible obstructions or damage

Any suggestions would be appreciated.

Thank you.

This topic was modified 3 weeks ago by chewie
Posted : 17/12/2025 3:37 am
chewie
(@chewie-2)
Member
Topic starter answered:
RE: Prusa MK3S Z axis not moving down past center (see video)

Well, I’ll be darned — I had previously tried pushing down the Z-axis, but I guess I didn’t apply enough pressure. I found this post where someone had the same issue: https://forum.prusa3d.com/forum/english-forum-original-prusa-i3-mk3-5s-general-discussions-annoucements-and-releases/mk3s-z-axis-problem/

I gave it a firm push downward, and sure enough, all calibrations passed!

Posted : 18/12/2025 3:36 am
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