[garagefela]

Hello all,
I have a strange problem with the test burn pattern from my laser tube. Long story short first up is that my power supply died and the link below is the background, read away if you like.

http://http://www.cnczone.com/forums/general-laser-engraving-cutting-machine-discussion/301792-g-weike-laser-wont-fire-help-trouble.html

I had purchased another power supply and all was good as it lit up my tube right away. The problem right off the bat was that it would not cut anything with the same power and speed settings as with the old power supply. It would only cut at full power and very slowly. I had decided to check the mirror alignment just to completely eliminate anything there and this is what I found.

The pattern on the test piece on top of the first mirror is an oval (as expected) but oddly with a clear unburnt section in the middle. I decided to shoot some test pieces directly in front of the tube and the same result. They are circles as expected due to being square to the tube but they are a concentric ring.

Very oddly is that from time to time it will shoot something closer to the normal shape that you would expect.

The tube exit window is clean so nothing on there is causing the issue.

I know the answer is that the tube is stuffed but why would that be?
How could the power supply damage the tube like this?
Damn it, it's only 16 months old and not really that many hours.

I'm off to replace the tube now, hopefully no more issues.

The pictures below will tell the full story.

Cheers, Michael.

Attachment 316674
Attachment 316676
Attachment 316678

[fixtureman1]

What is your meter reading the power supply may not be putting out the same amount of power as your old one

[garagefela]

Hi, thanks for the prompt, I forgot to include this info before.

The power supply appears to be behaving normally as the ammeter on the machine reads what I think it should around 30 mA at full load. I haven't checked with the resistor but am ok with the ammeter tells me.

Have put on the new tube today and still in the process of rechecking the alignment and will report back. Still has me stumped as to what could cause a tube not to put out a "solid" beam.

Thanks, M