Neje 40w "double laser" A40640 (not working-fixed)


I have been using LB with my chinese CNC: It has a “GBRL 1.1f” controller board, and the laser is an EiDevo 40w:

My conroller

My “old” laser head

I have just replaced the laser head with a NeJe 80w:

[NEJE A40640 Laser engraver / cutter Module ktis - FAC tech - 2 x laser – NEJE.SHOP](https://Neje 80w A40640)

But when I press “start”, the laser just fire a short shoot and nothing else.

Any idea?

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Got enough power supply?


I guess… If I press the test button on the board, it “work” (tested with both test button on the GRBL board and in the NeJe mini-board.

any help? :pleading_face:

First of all, you should change the title of this thread. NEJE does not sell an 80W module. The A40640 is a 40W (input power) module.

If you go to the first link you provided, the module product page, you’ll see at the top of the page a link to NEJE.WIKI. Click on that and then scroll down to the link for the A40640 product. There are installation instructions on that page.

It doesnt matter how you name it, a 40w laser one, a 2x40w lasers or a 80w one. It doesnt work.

Of course I have followed NeJe Wiki page regarding installation instructions. As the hardware seems to work, I think it is something related to the software (LightBurn?).

It isn’t 2X40W, it’s 2X20W to make a 40W module.

If your old module worked with the SW then the new one should as well, IF it’s wired and powered correctly.

The hardware seems to work fine, as I can fire the laser with 2 different test buttons (one in the NeJe board, one in my controller board).

Here are some videos of my setup:


Seems to me your TTL/PWM signal is not reaching the module.
You might want to check your board output pins to be sure you are feeding them to the Neje little converter board. My guess is you hwave PWM pins inverted
But would need to verify (maybe with multimeter)
You might want to check if the output of the board matches the Input C
However i would use GRD and TTL only (Input A) which might require modifying your cable by removing the 12v pin
Bad idea to mix the 2 power supplys imho

“Actually”… they do

Could you please state what the measured optical power of this diode laser is? Thanks

Well, if you believe in magic and fairies…
You won’t find that info on NEJE product website.

I am not saying the claims are right, i am just saying the claims are there.

And I’m not saying the claims aren’t there (you can find any kind of $hit on the internet), I’m saying the claim is wrong and it shouldn’t be repeated.

Can you open a new thread to discuss if this laser is a 20w, a 40w or anything else?

Ortur is guilty of the same - not to the same extent though - on the 2019/2020 modules, so mea culpa there too.Hopefully this shifts going forward.

Its a dual diode with a prism, roughly 10W optical output
In fairness, marketing material aside, respectable output for the price.


I have createrd a proyect in LightBurn, with a circle at 100% power, to take some measures with my multimeter.

A is 12v (as it should be, I guess).
B is 0v when doing nothing.B is around 5v when LightBurn is “burning”

C is 12v
D is around 0.20v when doing nothing
D is around 0.40v when LB is burning
If I press the “test” button, D is 12v and laser fires

Notice that if I switch off the A+B board (there is a little button at bottom left, or removing power), the laser also fires “at full power”

It looks like this little C+D board is broken or changing volts someway. Am I correct?

Are you using the extra power supply included with the module to plug into the Input A connector? THAT is totally necessary with this module. And, as gil says, only use the PWM and ground signals from your control board.

Yes, I am using the power supply that comes with the laser plugged in this “big round” black connector on the A square.

The controller has another power supply.