Possible to use M4/5 instead of S.. commands to use the K40 poteniometer?

[RobertH]

I have a glitch in my K40 where about 10-20 minutes in engraving jobs there is a power level increase (about 50%) for no reason and I can’t sort it out. I have checked every wire and connection in the system an all seems well. It almost appears to have to ‘warm up’ then the power spike happens and it stays there.
Anyways, I need quick ‘on the fly’ power changes (other than migrating the jobs into CNCJS) so I have to wire the power potentiometer back in on my Mini Gerbil.
That is fine as I don’t do grays scale work yet but if I am not mistaken that means only the M4/5 commands work for running the laser and the S… power commands are no longer implemented.
If my logic is right, is there a way to have LB output M4/5 for fills/lines instead of S… power level commands? (other than just editing the saved GCode).
Thanks again.

[LightBurn (Oz)]

There isn’t a way to do this, no.

[RobertH]

Probably just as well as it would really hamstring your awesome application.
I guess I just need a new laser.
ttfn

[JohanB (J.J. van Ballegooijen)]

Is it possible that the temp. of the watercooling is getting to high after 20 min. ?

[Grumpy_Old_Man (Anthony Bolgar)]

I would start by replacing the power supply and see if it fixes the problem before buying a new laser. It is either the power supply or the tube, and the PSU is the cheaper of the two to replace. My money is on the PSU as being the culprit behind the power spike.

[RobertH]

First of thanks guys for your input. Nice to know somebody feels my pain ;).

Here is a pic of what is going on. The image was burned starting at the bottom.

You can see how it gets progressively stronger.
Also, once it gets to a certain power level the laser no longer shuts completely off and leaves lines between the characters where normally it should be blank.
I have checked and rechecked all connections in the PSU including the power line to the tube and all is well. Coolant temperature remains cool as it is a pretty small job.
That being said, I guess the PSU is hosed. Which is weird as I can get a good engraving 5 minutes later. Just no rhyme or reason to it all other that it happening shortly after a job has been running.

Anyways, as my disability pension doesn’t go very far these days so any tips on where to find a reasonably price PSU?

Thanks again gang.