Laser will not fire k40

Machine: k40 nano

Board: cohesion 3d

Firmware: Smoothie I have a new board and I’m using whatever it came with
Problem/ Question: I have installed the new board and it movies the x and y but it will not fire the laser. The laser test button on the k40 still works so I know its not the laser. I am very new at this lightburn software so maybe there is a setting I am not turning on. I am not sure whats going on.

If everything is working except for laser fire I’d suggest you look at the wires that go from your LO & Gnd on the LPSU to the Laserboard. Pictures of your wiring of both the LPSU and the Laserboard would help.


So It was the cheap blue wires coming from the psu to the board. The end was not crimped all the way and the wires where out of the connectors I recrimped the wires and eveything is working now thanks for the help.


Great glad to hear it. I was just getting ready to reply to check the blue wires because the pictures don’t really show which wire goes to which pin, plus being all blue doesn’t help either. :slight_smile: But yea the blue wire bundle you have there is for Laser Fire and Gnd, the other two blue wires are unused by the Laserboard.

So dose that mean I can hook up a 24v air valve to the 24v pin on the power supply and use light burn to turn it off and on? Well with a relay

I believe Cohesion 3d would suggest running it off a separate power supply but you could.

This would be the more relevant link. Please consider whether your air valve/ relay meets the requirements stated here, in particular the power consumption limit, and if so, it should be fine to just plug a 24v relay into the screw terminal air assist out.

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