Laser not firing


I received my Onefinity and JTech laser a couple of weeks ago. I setup the laser this week and it would not fire with the M3 command, but it would if I flipped the switch on the JTECH controller to turn it on at 100%. After troubleshooting with Onefinity, we concluded it was a bad Onefinity controller. They sent me a new one, which I received today. This one is doing the exact same thing as before.

After plugging everything in, I powered it up, and cancelled out of homing. Then all I changed was reversing the Y motors since my rails are flipped. Then I tried M3 S10 and nothing happened. I went up to M3 S100 with nothing. So I powered off the JTECH controller and unplugged the cable going to the laser connector on the Onefinity controller. I issued an M3 S255 and probed the connector and got 0 volts, just like the first controller which we thought was bad. Then I went back and unchecked dynamic-power and tried again, with the same results. I can’t imagine I got two bad controllers in a row. What am I missing?


Did you change the “tool” in the Onefinity fly out menu to “pwm spindle” AFTER you swapped controllers?

They were both defaulted to that so I didn’t have to change it.

Hi Nate,

I would try doing the same sequence with the laser driver plugged into the onefinity and then see if it turns on. If it doesn’t, then check the voltage at the H2 terminal. It is easy to get to to check this.


You should see 3.3V here if the controller is working and the cable is good. It should also turn on the laser. Make sure you have it plugged into the correct port as well just to double check. Make sure you push it in all the way as I have heard they can get stuck a bit.


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I just wanted to follow up on this post and say, again, Onefinity and Jtech customer service is second to none. It turned out that I had accidentally hit the AC button on my multimeter. When I switched that back I was able to measure 3.3V all the way to the laser driver. Jay is sending me a replacement tomorrow. Can’t beat that!

Hi did you get a resolution to your problem as i have the same problem.
i can test fire from the back no problem, the fans on the laser and controller turn on but no laser on M3 S10 comands or any above that, tried reset but nothing.

It’s likely an issue with the JTech controller. You can find some debugging tips here: Laser Hardware Troubleshooting | J Tech Photonics, Inc..

My initial controller was bad and needed to be replaced because of these symptoms. After a while I started having issues with the laser not powering on at all or shutting off during a burn. This turned out to be a faulty power switch, which Jay replaced. Then I had similar symptoms again a year later which Jay helped me determine was the jumper wire not seating properly. I took it out, stripped off more of the wire shielding and I’ve had zero problems since.

Help. Cannot get the initial test fire for JTech 7W to go. Have tried MDI settings (M3 S??) tap play - nothing. Flip the switch on JTech controller to manual and laser fires. Have a file in Lightburn loaded on 1F by USB transfer…hit play and no laser but the program runs as if it is on the cut. Start it again, manually turn on laser and it burns the file but includes the tool path lines. Running 1F version 1.1.1. Have watched vids in Forum/FB/Instagram/YouTube and JTech ___ I’m stuck

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Sounds like your controller may be bad, too. Did you try the troubleshooting steps from the link above?

Little late to the party but I thought I would share my experience. I have not used my laser since I bought it over a year ago and was extremely frustrated when I could get it to fire manually but not with code. I checked everything. Finally while inspecting the laser cable connections I discovered that one of the pins was not fully seated, so I pushed it in delicately and guess what…it works now. Go figure, so happy it was not a controller issue. Hope this helps someone else…onwards and upwards!