Laser Starts then turns off. k40 Cohesion3D LaserBoard

I have a Chinese K40 I have installed a Cohesion3D LaserBoard I have been using Lightburn and
it has been working fine. After running a couple of projects the laser stopped “Burning”.
“Burning” I will defive burining as the act of the actual laser turning on.
I pause the project then resume and it starts again then stops burning after 1 second.
I pause and start and have the same effect.
I have thought it may be due to over heating so I replaced the water and let the pump run for a couple of hours and tried again and had the same result.

Do you have a way to check the pwm signal to the lps? Such as a voltmeter?

The PWM will usually reflect a percentage of the supply voltage, so a 5v pwm will read about 2.5v at 50% ‘power’.

That’s where I would start.

It’s more than likely it’s either the controller or the lps.

I think you have a TL connect on your lps, that is required to be low for the laser to fire. You should be able to measure any of these…

I’m not that up on a K40…


I have a Voltmeter I have been meaning to install. I will install it today and let you know

I mean a hand held meter to check voltages…


I do have a hand held volt meter. Where would I check this? I wish I was more electrical savvy.

That will work fine, and was what I meant…

Measure from ground on the board to the pwm that controls the laser. It should be the power percentage of 5 volts. 50% power reads about 2.5v…

That will tell you if the controller is telling the hardware to fire.