Identifying the control board in an older K40

Just purchased a 50w laser and it came with a free K40 which looks to have been well used.
Everything works, laser appears to fire well.

However it has what looks like 25 pin parallel serial port.

When looking online to upgrade the K40’s board to use lightburn, the stock boards always appear to be completely different to what I have, my machine has 3 boards.

I have tried to attach photo’s but I do not think its allowing me due to being a new user.

Any help or assistance is really appreciated.


Sounds like it has a Moshi board. It can be converted but will take a little more work to sort out the wiring.

A quick search I found this link that might help out.

Most of the K40 types are generally known… Can’t say I’ve seen one with a db25 on it…

If you can post a photo or put them on something like google drive and put the link here… that’s worst case…

I’m hoping @mcdanlj can move this to it’s own thread. This one is too long already… :face_with_spiral_eyes:

Welcome to the group

I’m sure we can help you to get it going…


Meerk40t has supported Moshi boards for a few years. :+1:

(See also the K40 Intro linked from the top of the page.)

It should have worked. You should be able to cut and paste pictures into place, or use the button with the arrow pointing up at the top of the message compose box.

Deleted above message as shared drive links didn’t work

New user can only share two links.

Dragging or clicking upload I get the below message:

/var/www/discourse/lib/discourse.rb:138:in `exec’:

Thank you for the warm welcome and assistance.

Thank you for the link, that helps greatly.

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Those links are to images you haven’t shared, it seems, so I can’t see the error. :cry: New users are set to be able to post five images, so that’s not the problem. :thinking:

The link and image limitations are spam management things. If you search for “moshi” and click around the site looking for other examples of the moshi to see whether they look similar to what you have, you’ll also probably do enough for the system to recognize you as not a new user any more, and you might find out whether your board looks similar. :smiley:

It has finally allowed me to upload a photo. (Main board)

I have searched for a moshi board but none appear to be the same as what I have.

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The text in the bottom left corner might provide a clue.

It looks ancient. The parallel port is definitely inconvenient.

Well, the good news is that the connectors do look almost the same as recent ones. The one on the right should be for the Y motor. The 12-pin FFC should be for the X motor and the endstops. The 6-pin connector on the left which only uses 4 wires has to be changed to a 4-pin one and then it should work with an M2 (or M3) Nano or any of the K40 upgrade controllers which got a connector for that 12-pin flexible flat cable.

The bad news is that your machine does use that 12-pin flexible flat cable, which is inconvenient if you want to use some controller which does not happen to have a connector for it. None of the DSP controllers have one, for example.

If you want to use one of those controllers, you either have to use some kind of adapter/breakout board or redo the wiring for the X motor and the endstops.

Here is @kwUK 's other photo, just so it’s inline with the rest of the thread.
They’ve done a lot to streamline the newer K40s, or at least hidden a lot of components under the cover for the laser PSU…

2004 Shenhul laser, by the marking on the board.

Even if you could reverse engineer that it has a parallel port which is impossible. You can swap that board out for probably an M3 Nano for USD$25 or so. The ribbon x, standard stepper y stuff is still the same today. In theory most of that stuff looks properly adaptable for modern lasers. You could probably buy a few different gcode controller cards for it. The thing that matters are the connections You need to fire the laser and control the stepper motors. You probably can’t get a computer with an old parallel port for cheaper than you could get a newer card with a usb port.

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I’ve have been given a known good M2 NANO board.

What would I need to do to get this wired in working?

What software would I then need to use?

From the K40 Intro at the top of each page here:

M2 Nano: Lowest cost, driven by K40 Whisperer , Meerk40t , or VisiCut open source options, or the generally inferior proprietary software shipped with the unit. Cannot be driven by Lightburn directly; MeerK40t can translate between Lightburn and the M2 Nano.

There’s lots of valuable information in the Getting Started with CO2 Lasers category that the intro is in. :heart:

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Think I may sell that unit then as no real use to me.

Thanks for all the help everyone, appreciate it.

If it has a TEST button on the front/top panel and you can manually cut 3mm baltic birch plywood in one pass manually moving the laser head slowly from left to right then mention that in your sales pitch. It identifies that the HV power supply and laser tube is working. But only do that with distilled water circulating through the tube. Running it without water moving will quickly kill the tube.

Otherwise you’d be selling a chassis needing a new tube, LPS and controller so maybe worth US$100 to the right person. US$0.02

Hi Dougl, Yes I have had it running and pushing the laser head slowly with my hand for testing that it was all working fine, had to get a pump for it and water so I didn’t damage anything as I have a larger laser that I use.
Just a shame for me that it has the parallel port and wont be easy for me to change to another board to use Lightburn which I am still learning to use, much better than RDWorks which I was originally recommended to use.

Will make sure to advise in listing that it is all working and cuts well.

Looking online they are listing around £300

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I’d try something like this first…

Seems cheap, lots of variants…


But his old board has 2 Atmel 8bit microcontrollers so what is going on on the parallel port is likely not just a serial stream.

It wouldn’t take much to rewire it to work with a standard Smoothieware compatible board if skilled in a bit of soldering, wire crimping and ohming out things with a multi-meter. But as it is with a parallel port for input to control it, who knows what pins were doing what and what software was used to wiggle those parallel port pins.


Or a data stream!

In general, the parallel port was also basically the GPIO header, and the USB/parallel port adapters are specific to printers. They are extremely unlikely to work for any other application of the parallel port.

(I did much of the early work on the Linux parallel port driver so I have some understanding of the difference between using it for a printer and using it as a kind of GPIO.)