K40 Laser not Responding with laserburn

Machine: K40 / Ribbon

Board: Cohesion3D LaserBoard

Firmware: Smoothie / I have a new board and I’m using whatever it came with

Problem: When i open lightburn and connect it to my k40 laser it shows that its ready (will not auto find) but when i click start or any other option like home or try and jog it on the X or Y nothing happens. Idk if i missed a step during the installation process but i followed the instructions on the site.

Did you check to see if you needed to install the smoothie driver? Screenshot of your Lightburn laser console may be helpful. You should see a Smoothieboard USB device under your ports in device manager. You could set Lightburn to that port rather than auto also.

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yes i installed the drivers even though im on windows 10.

IDK how Windows 10 lists devices but on Windows 7 the Smoothieboard device is under “Ports” Look under Ports and see what it shows, if the Smoothieboard is listed then use that port in Lightburn to see if that helps instead of Auto.

Can you provide photos of all hardware wire connections? Power supply and LaserBoard? Different angles please. Also, did you make sure the flat ribbon cable is in correctly?

Also, did you install the drivers because it wasn’t working or routinely after installing the hardware? It’s not necessary to do this with Windows 10 and can cause issues of its own.

Here are two screen shots showing the Device Manager on a Windows 10 computer that I’ve never used with the LaserBoard before. The left side is before I plugged in the LaserBoard, and the right side is after plugging in the LaserBoard. It shows up as USB Serial Device (COM4)

Shortly after plugging it in, Windows showed the following dialog in the bottom right of the screen.


There’s a good chance installing the Smoothie drivers on Windows 10 has caused some issues… Please see if you can uninstall the drivers and start over.

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Denzel, I couldn’t help but notice that your second photo shows a blue USB cable. If that’s the one that came with your laser we highly recommend replacing it with a high quality cable. The blue ones are known to cause issues.

i think i might have found the problem the Memory card that came with everything had nothing on it when i plugged it into my pc could this be my problem? and if so can you link me to where i need to be to put what i need on it? thanks alot guys.

the very first time i plugged it in i got that dialog at the bottom. and i was able to find my laser with the auto find in light burn but my bed size was something like 10mm x 10mm. then i seen a video on youtube on how to install properly and one of their steps was to put the memory card in before powering up and as so as i did that i started having problems. i could no longer auto find my laser and when i did find it i couldn’t make any cuts by pressing start or jog it around

Not finding a download of firmware or config on the knowledgebase or forum other than links to a dropbox so not sure if this is the most current version or not.

ETA the firmware isn’t current as I just did a file compare to the original firmware.bin that I received a few weeks ago and it’s longer & larger than the one in this link. I see Ray linked to the updated firmware so use his links. The config.txt does come back the same though.

That’s interesting - we flash the files onto each card here ourselves.

The cards currently shipping use just the config from Tim’s link and the new firmware file from here:

I need to combine those and put that up on the Knowledgebase.

You should put those files on the card and try everything again. If you still have issues, check what the lights on the board are doing (the Documentation Knowledgebase has an article on what they all mean), and ultimately you might want to try a different SD card.


thanks everyone i ended up getting it working after starting all over as suggested. i formatted the SD Card then added the firmware.bin and a new config.txt file and ran a job and my laser was finally responsive. now im having another issue. no matter where i place my art work in lightburn it tells me that my work is outside of the work area and am i sure i want to continue. i click yes but it still engraves in the same spot no matter where i move the art around.

i ran 3 different times.

You have Lightburn set to run from “Current Position” so when you start the job it will begin wherever the laser head is regardless of where you place art it in the workspace. As far as out of bounds, make sure you don’t have any pixels somewhere outside of the workspace try using a CTRL+A to highlight everything and if you find something delete it. Also make sure your machine size is set correctly in Lightburn.

If you want the design to be scanned in the same position as you have it in your workspace change to Absolute Position.


thank you very much

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