Good day good people of the LaserWeb community! You've helped me many times before

I think it was the FAN plug that has swapped pins (even wrong print on the bottom of the board).
Unplug the fan and try again. If it works, then the fan plus is crossed.

@cprezzi I disconnected the fan so I’m sure it’s not the problem and it still turns of when connecting laser out to TTL. I tried switching pins on that connection and that fixed the eleks board turning off, both seem to be working, but the laser doesn’t fire.

@Karlo_Krizetic That sounds like your Eleksmaker board has a mosfet that switches the negative side (GND) and the positive side is always powered.
In such a case you can connect the TTL in of the driver directly to D11 of the Arduino Nano (which is connected to the mosfet gate).

@cprezzi So one wire from the TTL should go to the D11 in the and the other to one of the GND? What’s the best way to go about this, soldering or?

Correct. I think soldering is the only option.

@cprezzi I tried that and laser didn’t fire, but then I noticed that both the laser and the TTL had swapped pins and when I switched them it worked.
But now I have more problems:

  1. Once laser starts engraving it doesn’t stop ever
  2. There is not difference in power, it still constantly fires at 100%

@Karlo_Krizetic Make sure you have M4S0 in the “start gcode” and M5 in the “end gcode”. M4 adjusts the power on acceleration and decelleration and stops the laser when not moving or on G0 (travel move).

Did you configure GRBL as advised on LW Documentation?
https://cncpro.yurl.ch/documentation/initial-configuration/31-grbl-1-1e/10-configure-grbl-1-1e

@cprezzi My GRBL is configured exactly as in the documentation (except for the machine dependent settings), my gcode settings were a bit different so I changed them to what you said but it made no difference. The machine doesn’t even need to be connected to the pc, as long as the power is connected the laser is continuously working.

If the laser fires without the arduino connected to the PC, then the cabling is definitely wrong.

Can you show a picture of the actual cabling?

@cprezzi Every black wire is connected to the negative as marked on each board. The laser is connected to the laser port on the small board and then the TTL from the small board is connected to the laser port on the Eleks board.
As soon as I turn the Eleks board on the laser starts. I also tried disconnecting the TTL-Eleks connection and in that case laser also works as long as the small TTL board is powered.
When the polarity on both of the connections were reversed only one board would be turned on at a time as I’ve described before.

Do you have two separate power supplys for the eleks and the driver board?

@cprezzi I have only one with a splitter, could that be the problem?

That should also work, if the cabling is correct. You need to make sure that GND and VCC is nowhere crossed, otherwise you make a short of the power supply.

GND of both boards is already connected via the power supply splitter, so you shuld not connect the GND wire of the TTL in of the driver board. Only use the plus wire and connect it directly to pin D11 of the Arduino Nano.

What type of laser do you have? If it is the one with the electronic board (driver) on top, then you need to remove that board and connect the laser directly to the laser out of the new driver board. Can you make a picture of it?

@cprezzi I tried opening the top of my laser module and first thing I found was a round PCB so I carefully removed it and below it is a complete mess, everything’s covered in some sort of a white silicone I’m guessing. Not if/how I can take it apart to make some sense of it.

Uhh, that’s not the one I expected. Those are the cheap versions witch have the diode driver cast in the white silicone stuff. That’s the reason why PWM power modulation was not working. Be carefull not to destroy the pins of the laser diode when removing the silicone!

@cprezzi Glad we know what the problem was at least.
I’ll try to carefully disassemble it, but it’s gonna be tricky since I can’t see anything. Will report the results.

@cprezzi I managed to dig out the driver and connected the wires that are going from the diode (can’t actually see, but they must be) to the new driver… And it still behaves exactly the same. Guess there must be something else causing this, should I try connecting the positive from the TTL to D11 now as you mentioned before?

Yes, just connect the + pin of the drivers TTL-IN to Pin D11 of the Arduino. The reason is, the normal laser out of the eleks board has a mosfet that switches the negative line, which doesn’t work with the external driver needing a positive signal.