Laser issues, cracking electric discharge sound and too much power

Hey. I hope this is the right section.

I bought a second “red and black” 130w co2 laser. First one is running fine, all good.

The second one - At some times I hear electric cracking noise, discharge somewhere near tube.

The first machine does perfectly engrave at 150mm/s and 9% power (mat finish, perfect).

The second machine even on 500mm/s and 9% power does engrave at least 0.5mm deep.

Both machines are supposed to be identical…

Any suggestions appretiated. Thank you in advance.

Update: So, cracking noise gone by itself and there is a little switch on tube PSU which enables power control.

No such luck… :sob:

Usually that ‘noise’ is from the anode hv arching from the connection or the wire to the frame. This usually is indicative of a failing tube.

Find where the arc is occurring… it most likely will leave a visible mark.

If it’s the lps/anode arching, I’d order a new tube.

You can check the TEM mode of the tube at m1, but it requires it to lase.

I’d suggest keeping it powered down until you fix it… that can’t be good on the lps.