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PWM Control issues (laser is firing more than set in software)

Hey guys,

I have some issues with my mini gerbil.
I tried to engrave some slate. I set power to 10% (my PWM Max Value is at 600 to get an output auf about 16mA with 100% not to overpower the laser tube).

But with 10% and 300mm/s sometimes it overburns massively. Then I unplug the mini gerbil and restart the laser. Sometimes it works, sometimes it fires again with about 100%.

Yesterday it started the engraving quite well with about 10% and during the engraving it overpowered (as seen on the image).


What do I wrong? Or is there a solution to fix my issue?! (Resetting the Mini Gerbil or flashing another firmware, I don't know, sorry I am a Newbie in the laser-game) 🙂

Uploaded files:
  • IMG_3861.jpg
  • IMG_3865.jpg

Hi, it can have various causes:

  1. Laser ground for PWM is bad hence it intermittently floats (laser outputs 100%)
  2. Laser power supply has a fault
  3. Laser software sends an erred G-code command e.g. S1000

I suspect it's number 1.

Re-seat the big power connector on the mini Gerbil. Sometimes the receptacle pins in the female connector are pushed up and don't make good contact. You might need to push them back in each position by pushing the wire or use an instrument screwdriver to carefully push it back.


Cheers, Paul awesome.tech

hey Paul, thanks for your answer.

I will try to re-connect the power-wire.
I fixed it with hot glue, so I have to peel it off before re-connecting 🙂

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