Mini with K40, laser fire problem

Machine: K40

Board: Cohesion3D mini

Firmware: Smoothie / Cluster_

Problem/ Question: I recently acquired a Mini board to replace the M2 Nano in my K40. Installed Lighburn trial on a Mac. First I had problems with the X and Y wiring and settings, but after some reading and trying, it was all fine, apart from a tiny little problem. With the default config.txt, when I start engraving or cutting, the head moves properly all the way, but it won’t fire the laser. Checking the config file, I found a line:
laser_module_enable, which was “false” by default. I changed it to “true”, now the laser fires, but the engraved image is just a black rectangle instead of the photo I tried. The edges are even darker, I tried to enable “overscan” in llightburn but that just made the rectangle bigger, with the same burnt edges. Now I can’t figure out what else can be wrong, can you please advise?

zoli, can you verify your laser is capable of firing at different power levels? It almost sounds like it’s firing at full power all the time. Please try the following:

Home your laser, then open the Console panel in LightBurn. and the type the following command followed by the return key:

G1 X10 S0.1 F600

This should move your laser head from the home position to the right, firing the laser at 10% power while it moves. The S0.1 represents the power, with 0.1 being 10% and 1.0 being 100%. You can modify the value if desired.

If you need to test more than once, just click the Home button in LightBurn and then send the command again. (Alternately, change the X value to a higher number to continue moving to the right.)

Our Knowledge Base page on PWM tuning is also worth checking out:

Once you run the commands to move and fire the laser at various power levels let us know what the results are.

(One more thing… do you have an mA meter that can show the output of the laser?)

Hi Pete,
Finally I could try it and no luck.
This command didn’t fire the laser at all.
I didn’t change a single thing now in the config file, and it moves, but no laser fire.
I do have an mA meter, and in that one occasion when it fired, it was constant power while engraving, instead of the meter moving as it did with the nano board.
What should I do next?

zoli, can you provide some photos of the board, wiring, and LPSU? Photos really help when we try to go through diagnostics. Let’s make sure everything is wired up correctly.

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