We test every laser and driver combo that leaves the shop here, but sometimes things happen in life and can go wrong.  Also, sometimes getting everything all working together with the hardware and software can be a bit of a challenge.  Here are a list of some of the top questions we get with both the hardware and software.  Hopefully this can help along the process of getting your laser set up on your machine and working smoothly.

Initial Setup Troubleshooting:

I just unwrapped my package.  Which connector do I attach the laser to?

Great!  You just got your laser.  First things first, we recommend if you are going to test your laser before you put it on your machine, make sure you DO NOT have it pointed in a direction that can cause harm to anyone or anything and always use the proper safety goggles.  That being said, your laser will attach to the farthest Mini Fit Jr. Connector on the edge of the laser driver in port H3.  This is very important.  Do not connect it anywhere else but terminal H3.  The following picture will show this:

-Plug the input mini fit Jr. molex connector from your mounting kit in terminal H4.  If you have your own input signal cable, then put it in screw terminal H2.
-Plug the wall power adapter into the bullet style power connector.
-Plug the laser fan cable into the laser fan JST port.
-If you have a remote reset cable, it goes into the JST port on the far right.

I plugged in the laser driver wall adapter, turned the key, and pushed the power switch and nothing happens.  What now?

First, you need to press the red reset button on the front of the laser driver.  This will enable the interlock circuit and allow the laser driver to turn on.  You should see the left LED go green and both the driver and laser fans should start to spin.  If the mode selector switch in the front is to the right (like in the picture) the laser should be OFF as well.


I have no laser light.  What now?

We are going to check to see if the laser is working without any connection from the computer or controller.  Here is the process:

  1. Check to see you put the laser in the correct terminal H3 on the edge of the driver board.
  2. Press the red reset button (if you have not already).
  3. Turn the key switch.
  4. Put your goggles on!
  5. Push the power button.
  6. Make sure your goggles are on, and push the mode selector switch in the front to the left in CW (manual) mode.  The laser should fire.  Switch it to the right to turn it off again.

For this test, the switch will look act like this:

If the laser does not turn on, then contact, or give us a call.

The laser works in CW (manual) mode, but I can get it to turn on with the controller.  What now?

First, check you GRBL settings.  We recommend using GRBL 1.1f to control your laser.  You can out how to load this in the following post here: 

You can send a “$$” command in UGS to view your settings and then look to see if you have the following:

$30 = 255 (max laser power)
$31 = 0 (min laser power)
$32 = 1  (laser mode)

Now that we have the settings correct, lets send a command to the laser.  With the new GRBL 1.1f for safety the laser will only turn on when in a G1 coordination move mode.  So, you will have to send the following command to get the laser to turn on:

G1 F4000 M03 S255

This will turn the laser on full power.   If you want to turn it on low power, then send:

G1 F4000 M03 S11

This will turn it on in low power so you can position the laser and also do focusing if needed.

In UGS, we like to create a macro with the laser on command for low power and Laser Off command of M05.  This way you can just press a button for it.  

I tried sending a G1 F4000 M03 S11 command and it still doesn’t turn on.  What now?

If you have the correct GRBL settings using GRBL 1.1f and it still does not turn on, then there is a problem with your connection.  Make sure your machine is connected to the controller and you can jog the machine.  Try sending the command again and see.  If this still does not work, then you will need to verify your output with a volt meter.

Start by sending the command “G1 F4000 M03 S255” and look at the signal at the controller.  If you have an X Carve, then it will be the Spindle PWM signal and GND to test the voltage.  If you have a Shapeoko3, then it will be on the Carbide board where you soldered.  If you have another machine, then look at where the instructions told you to set it up.  You should see 5V at this connection.  If you don’t, then check your screw terminal connection or your solder job.

If you saw 5V at the controller, then check at every connection on your way to the laser driver.  On the laser driver, you can check on the screw terminal H2.  It should read 5V on your meter when the laser on command is sent with full power.

If you still have issues, please contact for help.

Focusing Questions:

I mounted my laser on my machine, now where is the focus going to be?

The laser comes pre-focused to a distance from the base of the black heatsink to the work surface.

3.8W Laser = 1.5″
2.8W Laser = 3″
2W Laser = 3″
1W Laser = 3″

You can set the laser to this pre-focused position and start.  If you rather do a different focus position, then you can focus the laser yourself using the focus instructions.  Remember, the closer to the work surface, the smaller the spot can get.  The farther away, the larger the spot.  You can use the focusing instructions here to focus the laser:

Focusing Your Laser 101

I focused the laser, but my laser spot is a rectangle.  Why is this?

The 455nm lasers are what we call “multi mode”, which is a fancy way of saying they are a rectangle.  They are a semiconductor laser and emit from edge of the semiconductor, which happens to be a rectangle.

My focus doesn’t change when I rotate the silver thumb screw and is stuck at about 5mm no mater what I do.  What now?

The laser comes pre-focused at 1.5″ for the 3.8W and 3″ for the 2.8W laser.  However, if you try to focus the laser yourself, you might accidentally turn the lens way too much clockwise into the laser tube causing the lens holder to get stuck.  This can then look like the lens is only at one focus that is really close to the work surface.  To remedy this situation it might be a bit tricky depending on how much you turned the lens into the laser tube.  You need to take apart the lens assembly, remove the lens tube from the laser housing *without* turning the diode apart from the laser tube, and then put it all back together.  Here is how to do it:

Here is what the laser assembly looks like:


  1. If your lens is stuck, then try to rotate it gently counter clockwise without rotating the laser tube as well.  If you notice the wires rotating then STOP!
  2. If it is really stuck, then the silver thumb screw probably will be able to come off.  Rotate it off to expose the brass lens holder.
  3. Try to press the lens holder in while rotating counter clockwise to remove some tension on the spring to get it to come out without moving the laser holder.  If this does not work and the laser wires are rotating then STOP!
  4. You now will have to remove the laser tube from the heatsink.  Loosen the top set screw.  Pull the laser tube out the back of the heatsink.  Take a cloth to wipe off the thermal paste, or just leave it on.
  5. You will now be able to hold the from of the laser tube while you rotate the lens holder out of the laser tube.

6. Remove the lens holder from the laser tube and then hand tighten the front laser tube to the back laser tube.
7. Place the laser tube back into the heatsink, line it up with the front so there is no overhang, and then tighten the set screw on the top.
8. Put the thumb screw back on the lens according to the picture below:

9. Put the spring back into the laser tube and put the lens assembly back into the laser tube.
10.  Use the focusing procedure from the previous question to focus your laser.


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