Co2 Laser pulsing

Our EFR F6 is pulsing near the output end running close to full power, just wondering if someone can confirm if this is behaving normally?

What do you mean by that?
The best way to check your tube is to do a test on M1.

Pulse at mirror 1 looks well formed. What I’m talking about is the light at the end of the tube pulsing in and out like a piston, this is a built unit so we aren’t sure what looks normal or not - I haven’t found any closeups of the end of a Co2 laser tube operating. It does work, we’re just getting to the end of finalising one or two last small additions.

As long as your output on the M1 looks good with no signs of a bad tube, I don’t think it matters. With one of my 40 Watt tubes I have had the same phenomenon. I just wouldn’t have expected that from an F6 tube.
Is it as obvious when you “load” the machine with more than 25% of its capacity?

No worries, we had it running at 100% in this video, though have it wound down slightly at the power supply I think to around 28mA from memory.