JTech 24W laser does not turn on after being bumped

[Tango (Dean)]

I just received my JTech 24W laser and started burning a material test from LightBurn. I got about 50% through the project and I bumped the table holding the CNC. The laser turned off and now I’m not able to get it to turn back on again.

Thinking that it just tripped a motion sensor or something similar, I stopped the Onefinity, powered off the laser (the fans were still running) and then did a complete reset of the laser module (key, switch, button.)

However, I am unable to get the laser to turn back on again - either via gcode, or via the manual switch on the control box. After a complete reset of everything (onefinity included), I am able to get power to the laser (fans run) - but I can not get the laser to start again using either the manual switch or an MDI command.

I’m really have a hard time finding good documentation online in regards to the steps to fix issues, but I did find the post before in regards to the 7W laser released years ago. It’s somewhat relevant (the 24W control module doesn’t have the same access as the older models) - but I think I have tried all of the steps listed (my results in bold below)

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Answering the questions from: Jtech Laser Diagnostics Test:

@OnefinityCNC

If your laser is not firing as expected, perform the following steps.

1. Make sure the laser driver controller is turned on. There should be a green led on the controller once you’ve turned the key and pressed the power switch. You may need to push the red ‘reset’ button on the laser driver controller to get it to turn on. Once on, the internal fan of the driver and the laser head should be spinning.

Completed these steps with no issue. Control module will power on and I get one light. If I flip the switch, I am able to get two lights, but the laser does not turn on. Fans run without problem and there is power going to the laser unit

@OnefinityCNC

Next, ensure you are running the latest firmware: Firmware Update 1.0.9 (12/17/21) (Latest Firmware) (currently 1.0.9). For this test to work, firmware version 1.0.9 or greater MUST be installed on the controller.

Currently running Version 1.1.1

@OnefinityCNC

Select the “Laser (J Tech, etc.)” option on the dropdown on the “Tool” page of the flyout menu (starting in FW 1.0.9)

Completed and was able to run the start of the test burn without issues

@OnefinityCNC

Send the command M3 S1000 (max power) from the ‘mdi’ tab on the Onefinity controller and then test the voltage at a few places.

Laser does not turn on via the switch or via MDI commands. I do get one green light when the laser module is turned on and two green lights when manually turning on the laser, but no beam is emitted.

@OnefinityCNC

• Test the voltage at the output of the 0nefinity controller on the “laser” connector. Unplug the cable and see on the pins what the voltage is. It should be 3.3V+. If it is not 3.3V+ there, then there is an issue with settings or the controller. Ensure that your multimeter is set to DC for the correct reading.
• If it is 3.3V+ at the Onefinity controller, then plug the cable back into the Onefinity controller. Then check the voltage at the laser driver H2.
  It is here:
  
  You should see 3.3V+ there. If you don’t see 3.3V+ there, then it is the cable that is bad.
  If it is 3.3V+ at the Onefinity controller, then plug the cable back into the Onefinity controller.

The back of the control module does not have the same pin out as the image posted. If I disconnect the cable to the laser, I am able to get voltage

• If laser is turned off: 0V, 24V
• If laser turned on: 5V, 24V

I do not have the same pin out so I do not know where (or if possible) to check the voltage at the module. But, when testing the cable, I can see that power is being sent. The laser is just not responding to the voltage sent.

I am hoping that there is a simple reset or something, but I’m not sure if that’s a thing. The CNC is mounted on a 2x4 table with dual 3/4" MDF sheets as the top (it weights 100+ lbs). All this to say is that the table barely wiggled before the laser went off. I realize that “it’s a laser” and “you need to be careful” but this was barely tapped.

The JTECH site says “The laser head has a patent pending angle sensor integrated into the electronics to only allow the laser to fire when positioned facing downwards towards the work surface. If it accidentally gets knocked off the mount or is not on the mount, the laser shut off and will not fire.” This was significantly less of an impact that getting knocked off it’s mount, so I would think you should be able to start the laser back up again

[alden (Alden P Southwick)]

Have you tried adjusting the screw inside the laser controller in the back right corner? This screw adjusts the intensity of the laser beam for positioning your laser. Using a small screwdriver turn the screw all the way left and then right until the beam just fires on MDI m3 s10 input. This might fix the problem.

[Tango (Dean)]

Thanks for reaching out. Unless I’m misunderstanding how the min beam strength potentiometer/knob works, that only adjusts the beam within a percent or two of MDI value. So while it might be useful to adjust it at s10 (so that it doesn’t burn the material when zeroing), I don’t believe it would do anything when running the laser manually (by flipping the switch next to the lights which run the beam at 100%) or by testing it at a higher s-value such as s100.

The beam stopped working in the middle of a project, so I know the machine is able to give it a signal powerful enough to tell the beam to turn on - I just can’t get it to turn on at any signal strength at the moment. Appreciate the idea though.

[alden (Alden P Southwick)]

I had mine working when I first got it but then it stopped. This is what JTech had me do and it worked for me. If you haven’t tried it, it is worth a try. I had to turn mine almost all the way to the right to get it working.

[Tango (Dean)]

I appreciate that insight, I will definitely give it a try.

[Tango (Dean)]

Final Update

Reached out to JTech customer support and heard back within a day. They believe that the circuit board in the laser head might have gone bad. It was probably just a coincidence that I bumped the table at the time. Regardless, they are taking care of it and sending out a replacement.

Unbelievable customer support from JTech - all around very impressed. Thanks everyone to provide ideas.