Random M9 code being sent to controller

I have been having random M9 codes being snt to my SKR1.4 controller which stops my burns due to a error. I do not use M9 and do not see a way to turn it off. I keep loosing my burns due to it. Sometime the burn will finish out fine Other times it gets stopped and in the console M9 was the last to be sent out… How do I stop this problem? Thanks

post your .lbrn if you can

Tried File to large.

upload it on google drive, make it public and share here the link, otherwise is quite impossible to help you


It’s happened on other files to. I just rerun the file and the next time it runs fine…

save it as gcode and post also it here please, i want to check it with mine


Sometimes it will run the code 3/4 of the way through the burn than stop. With the M9 showing. It does not really have a set place in the burn where it pops up.

i’ve checked your gcode with mine and M9 is in the same position, at the beginning and at the end of file. I think there is another issue that causes your job to stop.

I thinks so to. Did it twice this morning. 3 minutes into the burn. Had no M9 showing. It just stopped with no way of getting it going other than hitting stop… Thanks for looking…

M9 is “turn off air assist”. (M7 or M8 turns it on)

True, But I never select air assist since I have not hooked it up yet. But LB is still throwing out M9"s I guess Lb adds M9 to the code anyways…

LightBurn turns off the air assist at the end of the job. M9 is a pretty generic GCode, and should be handled by all controllers.

This topic was automatically closed 30 days after the last reply. New replies are no longer allowed.