Hi all,
I received an MKS Gen v1.4 replacement for my Tronxy x1. Flashed it with Repetier and using RepRapdiscount full graphics display. Only problem I am having is that the Z axis only wants to go down not up. Wit power off I raise the Z axis and then power the board on and try the homing and all is good. Then I move the X and Y axis in both directions (no problem). However the Zaxis only clicks when I try to move it up. Swapped driver boards and still does the same thing. Checked ref. voltage and It is good. And now I am at a loss.

What stepper motors do you have?
What are you using for a Lead-screw?
What is your current ref voltage for the Z-Axis, and do you have dual Z-Axis steppers?

On My 3D Printers I have dual Z-Axis stepper motors and have to use almost double the ref voltage.

Edited 1 time(s). Last edit at 02/21/2020 01:34PM by Roberts_Clif.

---

Computer Programmer / Electronics Technician

Answering Roberts_Clif questions. My stepper motors are all sl42sth34-1504a, Lead-screw is 8mm (4 starts?), ref. voltage for zaxis is .63 with just 1 stepper. I managed to replace the damaged chip on the Melzi board and all motors move the way they should. I really like the MKS board and I would like to use it instead. I think it is very wierd that the z axis will only move down. Reversing direction doesn't seem to help.

I really like my controller style though its drivers are soldered to the controller.
Tried to replace the fried drivers without success, believe the replacement chips i purchased were not pin compatible.

Your stepper motor should be able to lift the Z-Axis wonder why it is not.

Did you measured the Melzi to get ref voltage for the MKS, if so you may want to tweak it up or down a little to see if a little higher or lower will make it work.

---

Computer Programmer / Electronics Technician

Didn't think of that because the x and y axis are working fine. I will try raising and or lowering the ref. voltage.

Just upped the ref. voltage and it worked!! Upped it from .63 to .73 and it moved up with no problem but to be safe I am leaving it at .76. Thanks!