Locked Gantry on K40 Mini Gerbil

Hi, I’ve installed mini grbl on my k40 come to try and cut something but the flag try seems locked. Can’t move it manually either.

Have an error:9

Can anyone help?

error:9 : G-code locked out during alarm or jog state

Does it say anything else in the console when you connect?



Grbl 1.1f [’$’ for help]

[MSG:’$H’|’$X’ to unlock



It homes on start up, hits the stops as it should. then after doing a job just before it hits the stops the gantry locks but the motors carry on.

When you say “the gantry locks” what exactly do you mean? The gantry is always locked (held in place by the motors) so the machine knows where it is. You’re not supposed to be able to move it manually (other than with the jogging buttons) because that would make the controller lose its position.

it judders while still moving, like something is preventing it from moving but it carries on and does move. kinda like if a stone were in the way I guess is the best analogy I can think of. through the whole cutting process its fine and when it starts up its fine too, its literally just after it completes a job

Then that is the rapid move on the way back from the job to the starting point, either accelerating too fast or moving too fast, and causing the stepper to skip. You’ll hear a weird buzzing noise when this happens. You can try lowering the accelerations a little and that would likely help, or the maximum travel speed for X & Y.

Thank you - I can alter this via console in LB can’t I?

$120 / $121 controls this right?

Yes, or Edit > Machine Settings.

I have adjusted this, and its moving much slower but its still doing the same thing.

Occasionally after a test fire (I wrote a macro) it did it too, and its like its catching on something :frowning:



Grbl 1.1f [’$’ for help]

[MSG:’$H’|’$X’ to unlock


It’s possible that one of the motor driver wires is loose - check that, as that could cause what you’re seeing. Make sure the laser is grounded properly as well - poor grounding and electrical noise will wreak all kinds of havoc.

I feel a little out of my depth. not too sure what I am looking at or for.

when I installed the mini gerbil one of the ground wire pins was out of the connector so I soldered it in to the connection and put it back in but that is firmly back in place.

I just don’t understand why it acts normal until it comes to homing

Just ran another piece and its 100% just ignoring the limit switches when homing

If the switches were broken or wired incorrectly, they wouldn’t affect anything but homing, so it’s not surprising.

I see- thanks for the help. what am I best checking then? what am I looking for?

really appreciate your help

I honestly don’t know enough about the Gerbil hardware to say. Check the wiring connections to the limit switches to make sure everything is plugged in where it’s supposed to be. There are commands in GRBL that will print the state of the switches.

Read here: https://discuss.inventables.com/t/guide-using-grbl-to-debug-your-homing-switches/16588

I will take a read of that - thank you. If I needed to replace the switches, something like the below would be fine I assume


I would assume so, yes.

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