I linked some videos of the problem.
This is a Chinese 130W laser cutter. It probably has actually been lasing for three hours. I got it a month ago. At 50% power, the laser will only stay on for a second or two seconds then it goes off when it should still be lasing. On the laser power supply, there is a red light than indicates it's lasing. That red light comes on when it should and the power supply makes a hissing noise while the laser is firing then stops making a hissing noise when the laser stops firing.... even though it should still be firing. The laser is aligned properly. At 20% power it will stay on, but the power is very very weak. It won't even cut paper. That's 20% power on a 130W laser. I've got diodes that will do that. It did have very good power at first. I have a purple light in the tube when the laser is triggered, whether it's actually producing a laser beam or not. The intensity and completeness of the purple light in the tube seems to vary with whether or not a beam is actually being produced. Water has been kept clean and cool.
Here are the vids. I had to take lower quality vids to get a workable file size.
https://sabercathost.com/4Sl3/50_percent_power_80mm_per_sec_ wont_stay_on.AVI
https://sabercathost.com/4Sl4/20_percebt_power_80mm_per_sec_ wont_cut_paper.AVI
https://sabercathost.com/4Sl8/SAM_0741.AVI
https://sabercathost.com/4Sl5/Laser_is_aligned.AVI
https://sabercathost.com/4Sl6/Should_be_full_spirals.JPG
I've given a look over the connections and they seem fine. I think something is wrong here, I'm just not sure whether it's the supply or the tube.
Thanks in advance.