Congratulations on your purchase of a Cohesion3D Mini Laser Upgrade Bundle!

Your package should come with the Cohesion3D Mini Board, 2 A4988 Stepper Drivers, and a MicroSD Card. Shown here is the base bundle with an additional optional GLCD Adapter.  You may also have ordered additional stepper drivers, adapters,and/ or endstops. 

The white JST Cable is no longer included and was for legacy installations only. 

Here is everything unpacked and laid out:

The MicroSD Card already has the firmware and configuration files on it, so just insert that into the board.  The A4988 drivers are the small green modules you see.  

  • Install the heatsinks by peeling the backing off the adhesive tape on the bottom, then stick them onto the black chip on the driver module, roughly as shown here.  
  • Take care that the heatsink is not contacting the header pins on the left or right edges. 
  • Notice the potentiometer at the top of the module, and that it has a flat side which should be facing up/ out.  You may need to rotate this about 45 degrees clockwise.  Ideally you would use a ceramic screwdriver.  Minimize your risk of shocking the module by touching something metal like a radiator with both hands or otherwise grounding yourself. 
  • Install the modules into the Cohesion3D Mini board.  Pay close attention to the orientation shown.  Installing the modules incorrectly can result in burnt modules and possibly the board itself.  The potentiometer of the A4988 is facing up and out to the top of the board. 

Let's take a quick break and talk about the GLCD.  GLCD stands for Graphic LCD and this is a great way to have a status display on your K40/ Laser Cutter/ other machine type.  If you did not get the GLCD adapter, scroll down to the "back to the laser" section. 

This is the GLCD Adapter for the Cohesion3D Mini.  It is an optional item available for add-on at the time of ordering, as is the GLCD module itself. . 


The back of the GLCD:

Ribbon cables installed (make sure you install them facing this way):

This is the orientation of the GLCD module on the Cohesion3D Mini, and you can see the header it goes on.

The EXP2 cable goes into this socket:

Then the EXP1 cable goes into the remaining socket.  I marked EXP1 with a zip tie for my convenience. 

Back to the laser:  Shown are some possible configurations of the K40.  There are multiple ways these come wired.  We will do our best to address the different ways and if something seems different in your machine than what you see here, please ask!  

Take a good picture of your stock electronics in case you need to backtrack later. 

I call this the "No Ribbon and White JST Connector Power Supply" Variant:

Loosen up the screws/ nuts holding the white panel in place.  Here there are 3 nuts, 2 on the bottom and 1 on the left side.  Removing the nuts was enough to free the panel. 

Unplug the wires going to the stock circuit board, remove the white panel. Unscrew and remove the old board. 

Secure the new board.  For the majority of customers, the screw holes line up and the new board is a drop in replacement.   For some, their board had a different mounting hole pattern and so some work will be required to make new holes to mount this.  M3 Hex Standoffs into to the white panel, M3 screws to secure the board, and a drill-tap combo bit set is a quick way to take care of this. 

Important Note as of 8/28/18: We have found that having the board directly mounted to the chassis can cause problems due to bad grounding and power surges and spikes from the laser power supply that can result in instability, disconnects, and in several cases the board frying.  We would recommend finding a way to completely insulate the board from the metal laser cutter chassis, this can be with M4 nylon standoffs, via 3D Printed holder, or just making a plate out of acrylic to hold the board.   The goal is for there to not be any direct contact between the board (in particular the mounting holes) and the metal body of the machine such as through the screws.  

3D Printable Holder options:

Put the panel back into the laser, it is placed at an angle so that all the connections are accessible.   The following pictures are for a specific wiring configuration: there is a power cable (blue wires, large white connector) 2 motor cables (the colorful wires), and the endstop cable (white wires). Alternate wiring configurations will be added here later. 

Plug in the endstop cable.  This is a polarized connection and should only go in one way.  

Next, the power cable.  Note the latch and how it mates with the wall of the PCB connector. 

Next, the X and Y motor connectors.  The important part is orienting the plugs correctly.  The wire colors and order get changed constantly.  When you home the machine later the head should move to the rear left.  If it moves a different way, power down and flip the appropriate plug 180 degrees.

Finally, I have hooked back up the optional GLCD.  Now is the ideal time to insert the MicroSD Card into the board, screw the white panel back into place, and plug in the USB cable. 

Here is the K40, converted, with an intermediate GLCD placement. Many people in the Cohesion3D Community have created new panels that hold the GLCD. 

Here is another possible wiring configuration of the K40.  I refer to this one as the "Ribbon Cable + Screw Terminal Power Supply" Variant.  Images were supplied by a customer, thank you!

Here is the stock M2Nano Board.  The flat white cable on the far end of the picture is the Ribbon Cable.  The small white 4 pin cable in the middle is the Y Motor Cable.  Finally, the large white connector is the K40 Power Connector.  In this case, notice that it has a notch on the side, and this notch is pushing the wall of the mating connector outward.  It is important to maintain this orientation. 

Here are 2 pictures of the wiring hooked up to the Cohesion3D Mini board. The ribbon cable is plugged in such that the metal contacts on the end face towards the inside of the board (and apparently this leaves a blue portion that faces outwards).  

The small white 4 pin cable plugs into the 4 pin header at the top of the Y driver socket.  The important part is orienting the plug correctly.  The wire colors and order get changed constantly.  When you home the machine later the head should move to the rear left.  If it moves a different way, power down and flip the plug 180 degrees.

Once again, the power connector pushes the wall of the mating connector outwards. 

A note to keep in mind: It is possible to plug the motor cable(s) in either way.  When you are homing the head should move to the left and rear of the machine.  If it moves the other way, you may need to flip your X and or Y cable 180 degrees to reverse the direction of the motor.  Make sure you are entirely powered off before fiddling with any wires.

Another possible wiring configuration with a 6-pin or other power connection. Your setup may require routing the 24v/Gnd wires from the power supply to the Main Power In screw terminals and the Laser Fire (L) wire to the (P2.5/BED) FET bed minus terminal. Identify the wires by using the markings from the existing board as a guide or by tracing the wires from their source, and confirm the 24v and Gnd Polarity is correct with a MultiMeter.  

Now is a good time to turn on the K40. On the Mini, there is a stack of LEDs.  

At the "top" is a red LED called VMOT.  This indicates that the board is getting 24v from the laser.

Next is a green LED called 3V3.  This indicates that the logic (brain) of the board is getting power. 

Finally are 4 green LEDs labeled L4 - L1.  After the board has booted, L2 and L3 should be blinking. L1 and L4 should be solid.  

The GLCD may make a high pitched buzz for a few seconds until the board has booted.  

A quick note on drivers.  If you have Windows, but not Windows 10, you need Smoothie drivers.  Please see here: or download directly via this link:

Ok, plug in to your computer via USB.  

Software Installation:

Lightburn is the recommended software.  You can download the 30 day unlimited trial from our page here:

When you are ready to purchase, you only need to get the $40 GCode version to work with the Cohesion3D.  If you have a machine with a DSP Controller, or multiple machines with both types of controllers, you should get the DSP + GCode version ($80).

The documentation for Lightburn is here:

Follow this guide to set up the software, but by default you must select Smoothieware:

Also, the origin of the machine in LightBurn setup step 6 is the FRONT LEFT.  I know the endstops are in the back left.  Homing Location and Origin are not the same thing. Origin is FRONT LEFT.  

The K40 Upgrade Bundle comes with Smoothieware CNC Firmware and a K40 Laser-Specific configuration file on the included MicroSD Card. Here are those files:

Questions, concerns, comments? Please post to the Cohesion3D Forum for support, here: