Fslaser 5th gen conversion

Has anyone converted a 5th gen fslaser 20x12 hobby laser? I would to install the laserboard and start using the light burn software. Any input would be appreciated.


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I just did one this week. It will take me some time to get the pics together and describe exactly what needs to happen and what parts are needed.


Thanks for the reply. I just received my board and have stripped down the controller from fslaser. Looks fairly straight forward, however, one wrong connection and …poof, release the magic smoke. I’m looking forward to seeing your connection instructions. Thanks.

Wait, what happened?

Oh. Reading. You haven’t killed anything yet.

Nothing’s dead yet. Haha. I haven’t made any connections. I’ve just been studying their connections and what they do. Stepper motors should be straight forward. I have optical endstops, not mechanical.

One question is the 4 pin laser PSU connection. 4 wires. 24v, gnd, 5v, L.

I’m assuming that I do not need the 24v wire(since the laserboard has its own 24V power supply)

I should still connect ground.

5v connection, not used on your board, however from my PSU i believe it powers the red “visual” diode laser that shows position. So, do not connect this to your board.

L(laser). connect as indicated.

As far as end stops go.

  1. Pos and gnd to emitter side? If so, should there be a resistor in line on pos side?

  2. Signal and gnd to collector side?

  3. Maybe some changes in firmware if needed for endstops.

Also, there is a wire connected to the emitting end of the co2 laser. Fairly small gauge and this wire is on its own connector with another wire next to it on the same connector that plugs into the fslaser board. Is this a gnd wire for the laser with a sensor on their board to tell if the laser is actually firing?

I have not yet looked up any schematics for the power supply that they used. I will do much more research and wait for your expert advice before I proceed with any connections.

Also, I did not order the lcd screen as friend of mine has several of them from older 3D printer builds. I’m sure I’ll have questions about it after I get the laser up and running.

Any and all help is greatly appreciated. I saw your product at MRRF this year and talked to the Lightburn software engineer. I’m really excited about your product and can’t wait to get it up and running. My wife asked, “so, this is going to make your laser run like a $4000 laser?” I told her that this board(and camera) will make a $400 cheaper laser run like a $4000 laser. It’s gonna make my $3500+ laser run like it should!

Thank you for your time.

Dave C

I just looked up the power supply that fslaser used. Im starting to get a much better understanding of the wiring scheme. I didn’t realize that the PS has an option for “low coolant level” detection. This will definately be incorporated in this conversion.

Also, I now have questions regarding PWM laser conrtol.

Dave C

Here’s the photo dump: https://www.dropbox.com/sh/ukp2udhk8tb6h6s/AAAFRrtw84HY-gtcASKcUxS6a?dl=0

Here are some quick thoughts as I scroll through it:

I unscrewed the right side panel. I had to pull one of the wires (it had a spade style connector) to the IEC plug in order to not put strain on it when I put the right panel all the way down on the table.

X and Y motors were easy - just take the wires out of the original screw terminal blocks and put them to the screw terminals on LaserBoard.

Endstops - the bundle of green and black wires all want to go to ground. You see them going to the ground on the power screw terminal at the top left corner of LaserBoard. As identified they are opto sensors which means there is an LED - I soldered I think 120 ohm resistors (feel free to check my color code) in series with the red wires then those went to 5v on the endstop row with dupont jumper wires. The white wires are the actual signals. They are wired to Sig on X Max and Y Max.

We need the green wire L to Laser Fire screw terminal and a Ground wire from the LPSU to Laser Gnd screw terminal. Since LaserBoard has its own power supply we do not want 24v or 5v from the LaserPSU.

Finally, the stock board had one very strange thing - you see the screw terminal plug next to the USB Jack? See that resistor across the 2 wires? They did something, perhaps a bit too clever, so I’m calling it weird. One of those wires - either the orange or blue one, is the return from the laser tube. It’s almost as if they were current sensing the actual firing amount of the tube on the stock board. The other wire is an LPSU ground. With that screw terminal block simply unplugged and left alone, it was arcing and the resistor caught on fire. We eventually figure it out. The orange to blue wire soldering was effectively directly connecting the laser tube return to LPSU ground.

I think the pink and orange wires getting soldered together had to do with bypassing some safety that was preventing the laser from firing. I honestly don’t remember.

I’ll have to dig up the config file. It will definitely involve tuning. I think I turned the speeds and accelerations down somewhat. I had to set both alpha (X) and beta (Y) to home_to_max and set the alpha_max and beta_max to the correct bed sizes. By no means a final configuration, but we were able to raster a bunny with it.


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I’m sure that is what they are doing. The weird thing is, I’ve seen a Gen 4 board from a PRO series machine and it did not have that wiring. I wonder what is so special about the hobby machine?

As per the top photo, my controller did not have the connector with the resistor.

Here is what I have coming from my lPSU. I see the green “laser” wire. But where does the orange wire go to on your board? It comes from the PSU for pmw control.

It was not my machine in the pictures, and I no longer have access to it.

This might help. The LPSU is a known model.

If I see correctly, it would appear that the Orange wire is in position 5 which is IN. I tied this to 5v which is the red wire. It looks like the FSL board did this also.

Then we can send pwm to L to control the laser:

Note that by tying IN to 5V, 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.

Thanks! Making some connections right now. Will let ya know how it goes!

So, in Lightburn, 100%=100 power and 50% = 50% power from laser power supply and so on?

That’s what I would expect, a one to one corelation in regards to power output of the laser.

That’s funny.

We usually avoid this because the K40 and other such lasers come with a pot to set the power which we use to set the max power, read:

Success!! She’s up and running. Now to dive in and learn the subtleties of the Lightburn software. Maybe even a few more config settings to fine tune it some more.


We should probably compare notes on that at some point…

Sure thing. I’ll start writing out a detailed process of the conversion. Right now it looks a bit Frankensteined because some of the connections were terminated with a different colored wires and connectors. This was just for convenience to get it working. I will reterminate the connections with proper colors and clean it up some and document. Then we can compare and edit.

Today I will be working on a mounting solution for the board and designing a holder for the lcd screen. I might browse the interwebs for some designs and then just modify it to my needs. If there aren’t any good ones already out there, I’ll start from scratch. I’m gonna add some switches for coolant on/off and one for air assist manual override.

I’ll also post my configuration settings.

Thanks for the help so far. By the way, is it possible to get the pin schematic for the lcd screen hookup connections.

Dave C

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No worries on the pin out for lcd. I just ordered the connector from your website.

Just in the process of converting my 5thgen over to the laser board.
were you able to use the existing water flow safety switch or did it need to be replaced with a 2 wire model vs the current three wire one in the machine. if you used it how did you wire it into the system?

Make sure to fully review the images in Dropbox linked in this post:

If I recall correctly, I left the door magnetic switch wired directly into the LPSU.

I would not have connected the water sensor to the C3D board at all. So if it was connected to the original controller, then it is left disconnected. If it was connected to the LPSU, I would have left it as it was.

The water safety switch in the machine was attached to The fsl board. The switch itself Has three wires and I was wondering if it could be put in series with the magnetic door switch on the lpsu and if so how the wiring would look
or do i needed to purchase an analog style flow switch that is only two wires for that?