I'm just getting started in 3D printing by rebuilding an old machine from scratch updating firmware etc. It is all wired up and I am calibrating and completing tuning before a first print.

I am having a weird problem in that when I click "home X" button in Pronterface, my dual Z axes steppers move in the +Z direction and crash. If I home Z via Pronterface, the Z-axis behaves correctly (moves in -Z direction until it bumps off the limit switch). I am using an MKS GEN L V1.0 board and Marlin v1.1.9

If I move thr Z-axis via Pronterface in the +Z direction, it moves as expected. Both Y and X axes also seem to work okay and respond to commands normally via Pronterface.

Sending a G28 X command also results in a Z-axis activation and crash. Sending a G28 Y command has the same result.

Any ideas on how to resolve this?

  • $\begingroup$ Most likely a firmware issue. Marlin 1.1 is quite old. I'd suggest getting the latest Marlin firmware on it. I have a the same board as you and it came shipped with old firmware. It will also help to post your Marlin Config. $\endgroup$
    – Artichoke
    Mar 7, 2021 at 5:53
  • $\begingroup$ It is normal to have some Z-activation when homing X and Y. This is to protect the nozzle from hitting the bed or anything printed on the bed. But a centimeter should be enough, like #define Z_HOMING_HEIGHT 10 $\endgroup$
    – dotswe
    Mar 7, 2021 at 7:03
  • $\begingroup$ Maybe you could post your configuration file on PasteBin and share a link in comments. If wrongly configured, others can copy relevant parts into your question and answer the question. $\endgroup$
    – 0scar
    Mar 7, 2021 at 8:13

1 Answer 1


Found the issue with help here! My Z-axis homing height was not set - I set it to 4 mm but found that the Z movement is way off (actual Z movement is more like 15 cm!).

I will update to the latest firmware as suggested.


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