Geeetech i3 X updated merlin now Z-axis homes in the wrong direction

My printer is a Geeetech i3 X and I just updated Merlin to version 2.1.2.5. Unfortunately now when I home the Z-axis moves in the wrong direction and I can't figure out why or what to do.

All of my endstops are minimums and the Z endstop is inductive. All of the axis move in the correct direction when manually moving them but just the Z axis goes up instead of down when homing and has to be shut off. Oddly it also seems to ignore the endstop completely. If I trigger it with a piece of metal the printer just keeps going up.

I tested my endstops with the M119 command and they are all working and triggering on/off when expected. The firmware is set to home to minimum and I am using the config for my printer off of the Marlin GitHub. The only change I made is to invert the endstop logic for the Z-axis because my inductive probe is NO instead of NC. Again, after this it triggers normally except that the printer ignores it during homing.


I really can't figure out what the problem is...

In Marlin 2.1.2.5 , to modify the "Z_PROBE_ENDSTOP_INVERT" setting it to "true" if "false" or "false" if "true" should reverse the Z-axis homing

"this is not the right code look below"

Edited 2 time(s). Last edit at 02/23/2025 09:40AM by Roberts_Clif.

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Computer Programmer / Electronics Technician

Sadly, I can't find that line in configuration.h
I used Ctrl+F

Edited 1 time(s). Last edit at 02/22/2025 06:52PM by Daveseller20.

Did you mean Z_MIN_PROBE_ENDSTOP_INVERTING?

Sorry did a quick search posted what came up without checking

// Invert the stepper direction. Change (or reverse the motor connector) if an axis goes the wrong way.
#define INVERT_X_DIR false
#define INVERT_Y_DIR true
#define INVERT_Z_DIR false

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Computer Programmer / Electronics Technician

No worries, thanks for offering your assistance.

I tried that but unfortunately it still ignores the probe (even though M119 reads it correctly). Also now normal movements are backwards.

Edited 1 time(s). Last edit at 02/23/2025 11:53AM by Daveseller20.

Are you still having problems.

Post the original working firmware I will see what these setting should be for you.

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Computer Programmer / Electronics Technician

Yes I am unfortunately... If you mean the firmware before I updated, I don't know if I have it anymore as it has been so long. Let me search for it.

Yeah it looks like I don't have the old firmware anymore so I have to start over.

OK.

Home the printer and tell me if the X & Y travel in the correct direction toward to end stop switch else stop the printer before a hard stop occurs.

If this is correct let it continue to the Z axis ravel in the correct direction toward to end stop switch else stop before it hits the bed

Post results.

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Computer Programmer / Electronics Technician

X moves in the correct direction then it goes to Z (before Y) which goes in the wrong direction and continues even if I manually trigger the end stop. If I reverse Z, same result but Z is reversed. It still seems to ignore the endstop trigger.

Same result so far with every Marlin V2 release.
I am using the Geeetech I3_Pro-GT2560 configuration.

UPDATE:

I found that if I trigger the z-probe multiple times while it is going up, it will stop, home y correctly, then Z will go down like it should. Z then also triggers correctly and stops on the way down. However it does try to home with the bed not underneath the probe and no idea why it goes up first and needs multiple manual probe triggers to then home normally.