Laser stops at higher mA

Hey Don, I put it up to 5mA and with a pieces of paper over mirror one and can confirm that the piece of paper was unharmed.

I moved the paper to the exit of the tube and still the paper survived,
Hold the paper at the tube I turned down the power and when it go to 3mA the paper got hit by the laser

Forgot the photo - so I will get one shortly

At the 10ma* level is there a plasma (purple) beam in the tube??

  • I assume you are reading the 10ma on the analog MA meter.

Is would suggest that the tube is damaged and not lase-ing above 5 ma
Or
the LPS is not outputting the proper power above 5MA

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Hey Don - yes at 10mA the laser is still firing and can see the beam in the tube, though it does appear to curve at the very end

Yup! The visible plasma isn’t the laser, it’s how energy is pumped into the (entirely invisible, far-infrared) laser beam. The anode and cathode are rings at the ends, so the electrically-driven plasma will naturally have to curve a bit to reach them.

I did not see a response to this question?

It might be useful to turn out the lights and open the control panel and laser tube covers from a distance look and listen for crackling or arching around the tube or the LPS.

Keep body/hands away from high voltages.

Hey Don, yeah no crackling that I can hear. everything sounds normal when it is running but I will see if I can see any arcs (my machine is grounded too if that makes any difference).

I have also ordered some new tubes today just in case

Hey Don - Checked tonight and definitely could not see or hear any arching

So I really have no idea what part of my laser is failing, so far I have ordered new mirrors, lens, air assist, & tubes but guess I might as well order a new power supply as it could also be that.

Is there any particular power supply that I should look at?

Here are our current recommendations.

Thanks @mcdanlj LPS (Cloudray) ordered as well now, guess I will just replace items one by one and hope that one of these fix the issue

if your tube was not outputting any power above 3mA of current(at tube output) and you replaced the tube to no effect, checked the wires from the tube back to the LPS for arching then it’s likely the LPS. Air assist, mirrors and lens have no effect on this since nothing is exiting the laser tube. seems like an odd failure and I too would have guessed wire arching at high voltage with higher current.

Need a picture of your supply so you can pick a new one the will not require rewiring.


It is either your tube or your LPS it is often hard to be sure of which one. You said you ordered a tube so I figured you would install that and see if the problem was fixed. Then if not the LPS would be next.

You arent wasting your money in any regard because both these parts will eventually fail.

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I get 404 errors on some of these links.

if you saw ones other than the LPS links I just fixed, just mention them in comments at that page. (Or I guess fix them if you find them, of course…)

Thanks for the help @donkjr, this is the LPS i ordered Ebay LPS

Don’t think we have a picture of your current supply?

Just insure the connectors are the same :)!

Looks the same (insert unsure confident statement)

That looks right :+1: :+1: :+1: :+1: :+1: