80watt tube trouble

My 80 watt laser will fire and burn at power setting 30 or below but not at higher setting. Checked the power supply at different and its putting out the right milliamp signal. at 30 it will burn paper at the end of the tube and when i set the meter higher the tube will not burn paper at the end of the tube. I think the tube is going bad. am i right? this happened all at once while adjusting contrast doing a pic.

So how many miilliamps is the tube drawing and at what power setting?

At power 10 its 3 milliamps at 20 6 milliamps.at 30 its 6 milliamp.at 40 its 16 milliamp. at 50 its 20 milliamps. at 60 its 22 milliamps. at70 its 25 milliamps. at 80 its 28 milliamps

correction at 40 its 14 milliamps

Hmm. Well, those numbers look reasonably normal. You’ve got 6 mA listed for both 20% & 30%, i assume that’s a typo.

But you say it burns fine at 30% and below, but not above?
Is the color “normal” or is the plasma getting whitish?

Since the current at various settings seems normal enough It does sound like it might be time for a new tube.

how old is it?

I recieved this unit in mid june

This sounds pretty similar to what I’m seeing with my 90W RECI W2. Tell me, at the power settings at which the tube is still working do you have less cutting power than you used to have? Mine can’t get through 3mm MDF any more.

I can’t give you an answer as to what’s going wrong, I’m afraid. The crowd that sold me my machine tells me my tube is bad.

I’ve swapped the HV PSU and I’m getting the same result; as soon as I go over some threshold the tube just stops emitting, even though there’s a bright purple plasma arc down the centre of the tube. Same mA in, no beam out.

yes mine is doing the same as yours. As of right now i am waiting on a new 80 watt tube to arrive that i ordered. My power supply checked out ok.

Probably not the answer, but easy to check.

It’s worth noting that it’s a lens rather than a mirror (although with an internal semi-reflective surface), and pretty fragile.

From the Reci model W instruction manual:

3.7 Notices
The surface of beam output lens cannot be scrubbed with any tools such as cotton balls, otherwise the power will be serious affected. Here are several methods for cleaning.
(1) When the lens is contaminated, do not use the laser tube;
(2) Blow the lens surface obliquely with balloon;
(3) If the above no effect, user needs to remove the lens and use a cotton ball with a little alcohol to rotate the lens.
(4) No need too much alcohol, but the glue layer of the adhesive lens cannot be touched in case of gas inside escaping.
(5) The laser cannot be used till alcohol evaporating.
(6) Do not scrub the lens with acetone. The best way to protect the lens is keeping the environment clean. (7) When testing the beam on plexiglass, please keep it 300mm from the mirror.

How you want to interpret that is up to you, but if you’re going to scrap the tube anyway it’s worth a try. It certainly shouldn’t be part of your regular cleaning routine though.

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