FSL Gen 5 Hobby Laser Conversion, Stellaris Board

Machine: Full Spectrum Laser Gen 5 Hobby

Board: Stellaris

Firmware: LightBurn

Problem/ Question: I wanted to first of all thank you all for sharing your insight and expertise on this forum. I have read over many of the posts and responses here and you have convinced me that it’s possible to make a laser work better if you’re willing to put spend the time into it. We all benefit from your knowledge, so thank you for that.

As to my question, has anyone come across a wiring diagram for the old Stellaris board? I just ordered the parts from Cohesion to upgrade my FSL laser and was able to find a diagram for the old control card here, but I think it’s somewhat different than the Stellaris board that I currently have.

Here’s the post that brought me here initially

Here’s the list of items I purchased from Cohesion

This is my first time working with circuit boards, and I would greatly appreciate any insight you could share with me.

Thank you all,

Hi Chris,

Welcome to the forum! I have upgraded your trust level so that you can now upload photos.

Please provide clear pictures of your machine, control panel, board, other electrical components, and wiring. We need to see how and where everything is connected.

If this 5th Gen Schematic is what you are referring to, it’s probably the closest thing to your board that we have access to. We can help guide you for the connections.

Thank you for your response, Starla. I have attached the requested photos below and I can provide additional photos if needed.

And yes, thank you for providing the link to the Lasergods Gen 5 Schematic; that is the one that I was referring to. It has quite a few differences when compared to the Stellaris board, so I have had some difficulty making the comparison.

(I have labeled a few of the connections that I was able to identify and those should be visible in the photos)

FSL Hobby Gen 5:

Power connection:

X-axis with optics:

Power supply wiring (1)

Power supply wiring (2)

Stellaris board (1)

Stellaris board (2)

Stellaris board (3)

Stellaris board (4)

Stellaris board (5)

Thank you again,

Thanks, Chris. Can you get one of the board in its entirety that shows the labels for the blocks / pins, please?

Certainly. Going from left to right along the top of the board, the 5-pin connector on the upper left-hand corner is for the power/control; the 5-pin connector to the right of that is for the limit sensors; the 4-pin connector to the right of that is for the Y motor; and finally, the 4-pin connector in the upper right-hand corner is for the x motor. Other than that, I didn’t see many labels.

Thank you for your response,

Hi Chris,

Thanks for the photos. I adjusted the brightness to be able to read the labels, so pardon the over exposure, but hopefully, this helps.

It appears that you have the second model laser power supply, covered in our LPSU Guide. The last “L” terminal on the third block is unused.

image image

We need the L wire from the middle block connected to the Laser Fire screw terminal and a Ground wire connected to Laser Gnd screw terminal on the lower left corner of the board. Since LaserBoard has its own power supply we do not want 24v or 5v from the LaserPSU. These appear to be connected to the block in the upper left corner of your board (or what you had marked as the PWR plug).


On your LPSU, it appears the orange wire is in terminal 5 on the middle block, which is IN. This will need to be tied to 5v, which is the red wire in the third terminal on the far right block. Note that by doing this, if you ever press a physical test fire button like the one on the LPSU, or you run at 100% power in LightBurn, you are firing at 100% of 100% power, and this will degrade your tube’s life. In the linked post, you can see they soldered these two wires together and prepped to protect with heat shrink:


The 4 pin X and Y motor connections on the upper right side will be wired directly to the screw terminals at the top of the LaserBoard. Check your motor coil pairs to make sure the wires are paired properly to the terminals.



If you plan to use the existing optical endstops and purchased the connector pack & vitamins kit from the list you linked, see the 4 Wire Optical Endstops section of this article: Installing Endstops / Limit Switches

If you also purchased the 2 wire limit switches we carry to replace the existing endstops, that is covered under the 2 Wire Mechanical Limit Switches section in the same article above, depending on which solution you decide to use.

Your machine does not appear to have an mA Meter. We recommend installing it so you know how much power output you are actually using when firing the laser. Set up is covered here: Connect an mA Meter

Any protection switches like your lid safety and/or water sensor should be wired in series to the P (Protection) and G (Ground) circuit on the LPSU and do not connect the the LaserBoard. If you also want to put a potentiometer in, we cover that at the bottom of the previously linked LPSU Guide above, and you can find some reference for both of these installations in this thread as well: Just want confirmation and clarification on PSU wiring before I do something stupid

For the configuration changes to dial in the physics for your machine size, review our Larger Laser Machine Installation Guide.

Let us know if you have any questions.

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Your original FSL 5th generation board looks exactly like mine that I had before the conversion.
Here is a link to my conversion plus some links to other peoples conversion problems/solutions.
Also included some links to other FSL 5th generation conversions if it helps.

A IMPORTANT note… The vitamins kit does NOT have the correct resistors to convert the FSL optical end stops to work with the Cohesion 3D board.
You will need a 10,000 ohm resistor and the 220 ohm resistor for each end stop to make this work. See middle link above.

Does your system have a water flow sensor ?

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Starla, Thank you for your thorough and informative response. I’m grateful to have that information about the PSA and I really appreciate your taking the time to make comparisons to my photos. I had been unable to find the information that I needed regarding safety switches, and I thank you for passing that information along.

I have opted to try for the 2-wire mechanical limit switches, but I’m not exactly sure how to install them. I was able to review the Installing Endstops / Limit Switches guide that you shared (thank you for that), but I’m not exactly sure how / where to mount the switches along the X and Y axes of my machine. Would you happend to know how I might go about that?

I have included some photos below for your reference.

Thank you again for your diligent handling of this query,

Tom, Thank you for sharing these resources with me. I had wondered about the optical end stop and had just decided to go ahead with a mechanical end stop in the mean time. I appreciate the diagram you provided in your conversion post as well as your caution regarding resistors for the end stops. I’m glad to know that you were able to make the conversion from that Stellaris board–I had my doubts as to whether I’d be able to do it myself. Thank you for sharing.


Thanks for the images Chris.

The main thing is making sure that they are triggered in the upper left because your default configuration settings rely on this location as “Home”. Otherwise, if you prefer it to home to the upper right, we will need to make some other changes. In the Limit Switch article, looking at the image of the bed, you can see where the optical endstops are located for reference.


Mount the X axis limit switch where the head will depress it to the far left (X MIN). This is typically below the mount for Mirror 2, so that it moves with the carriage arm. You may need a bracket to attach it to. Here’s an example of one installed that is being triggered by the head moving far left.


You can mount the Y limit switch to the back side of the mirror 2 mount (as in the image below) or to the gantry itself, in the upper left corner (near where the A Homing location is in the bed picture above). You may need a bracket to mount to the gantry. This is Y MAX, so you will connect the endstop the respective header on the board.


If we look at your photos, you can see that the optical sensor requires those metal protrusions to go between the slot to interrupt the light to sense that it is triggered. For the limit switches, you just want to make sure that the switch is getting depressed properly to trigger.

The optical sensors are really easy to convert. You just need two resistors for each optical sensor assembly. The wiring is the same. Just cut off the the end that went to old FSL board, solder in-line the resistors.

Here is a picture of the wires coming from the FSL optical sensor going to the new connection points and the connector

If you need more picture just give a shout out as the converted FSL is just down the hall from me.

Hi Tom,

I’m curious why you are saying our vitamins kit does not work? We’ve had several people successfully use it to get set up for these type of endstops. You wired your endstops in a different manner than the covered method where the emitter and the cathode are wired to Separate Power IN in the upper left hand side of the board. Since Chris mentioned being new to this, I didn’t share your method because it involved more setup, trying to keep it simple.

Thank you for the photos and instructions on mounting the switches, Starla.

I see what you mean about positioning the mounting bracket–that makes a lot of sense.

If I did decide to set the switches at X-max and Y-max, would I just need to make sure that I connect the to the respective X-max and Y-max headers on the Cohesion board?

Thank you,

Correct, but the limit switches would need to be installed in the upper right hand corner on the gantry rail.

You would also need to make a configuration file change to set your alpha_homing_direction to home_to_max (far right). You can follow the same concept from the Larger Laser Machine instructions I shared for how to update the configuration file.

Then, you’ll want to test the limit switches and make sure they are triggering properly.

Also, one more note - LightBurn will still keep the origin in the lower left corner. You are telling the software where 0,0 is located in your work area, which differs from the homing location. You can set LightBurn to start at different job origin points or positions and even have it finish in the location you want versus going back to the origin point at (0,0), after a job completes. More information: Coordinates and Job Origin

If you want confirmation on the wires before turning on, feel free to post, because it can cause damage to the board if the endstops are not wired correctly when they get triggered.

I was basing my information on this link about 1/2 down. Michael Stone was trying to wire up the vitamins kit to his FSL 5th gen system and could not get it to work.

I posted pictures of the way I wired my system in that link based upon the optical switches in my FSL 5th gen system.
After he wired his system up like I had wired mine he wrote back
Tom, wiring the sensor the same way you did worked.”

I was just giving Chris the information on how to wire the existing already installed FSL optical switches that were working for two people with a FSL 5th Gen.
I was basing my view on the failure of Michael to get his vitamins kit to work with the existing FSL 5th gen optical switches but he was able to get them to work with the two resistors I suggested and my supplied wiring method.
I did not even get the vitamins kit as I already had the needed resistors
of 10K and 220 ohms on hand…
As for keeping it simple for Chris, I would think removing and installing mechanical switches would actually be harder and more time consuming than cutting off a connector and adding two resistors with a new connector to an already existing working optical sensor…
But then, that is for Chris to decide…

Thank you for clarifying, Tom. Correct, the vitamins kit will not work with this wiring set up, but it does work for the solution we cover in our documentation, which is how it was done in that original photo dump post that Ray shared.

Perhaps Cohesion 3D could add 4 more resistors (2 of 10K and 2 of 220 ohms for Min X and Min Y) to the vitamins kit so more conversion solutions could be covered. As more people want to convert their FSL 5th Gen to a Cohesion board and LightBurn software it would smooth the conversion.
The additional component cost would only be a few cents…

I was thinking the same thing. I’ll ask about it. I appreciate the info you’ve provided and I’m sure those converting find it helpful as well!

Thank you both for your feedback, Starla and Tom.

Having looked over both solutions, I think I’ll stick with the mechanical switch until I feel up to the challenge with those resistors–though I think re-wiring the original FSL optics like Tom suggested would be a more elegant long-term solution.

And Starla, I’d love to have you walk me through wiring those endstops to the board if you don’t mind–thank you for asking.


For the mechanical switches we carry, the red wire should already be connected to NC and the black wire to Ground. Just to confirm, this is the type you have, correct?


See the far left example below for how to connect the two wires to the board. The silkscreen labels above the male connectors will also show you which pin is which.


V+ is unused for these. You’ll hook NC (red) to Sig and Ground (black) to Gnd on the X-MAX and Y-MAX endstops header row.

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