[frStudent]

Hi,

I bought a K40 which arrived with a broken tube. I ordered a PST C45 tube (850mm, sold under Cloudray brand). The coolant is demineralized water (no specification on purity,bought in surpermarket,sold to refill car batteries and make vapor with cloth irons).

The day when I installed the laser and the next day, when I tried the "laser test" button to create short pulses (for laser alignment), I got some noise and a purple light, more noticeable with higher current (on this video,I used about 3mA, 5mA and 10mA) :



Then this morning, I wanted to remake the same video with the exhaust fan turned of and moving the microphone from the laser to the PSU to try to understand the problem,and I got very different result (5mA, 10mA and 18mA) :

https://www.youtube.com/watch?v=Ja1Qix5NvxU

I also have a video from two days ago (the day when I installed everything) where the 3mA pulse looked nice like this morning video, and the 6mA pulse looked unstable, dimm and was noisy like the first one :

https://www.youtube.com/watch?v=GUztkfWfM5M

The only difference I can think of are:
- Variation on the output of the wall power outlet ( do not have the more stable current here)
- Dissolved gas in the water that may have went out (this morning, I saw bubbles in the hosing that where not there yesterday and which looked like the bubble on the side of a sparkling water bottle)
- The disconnected 24V fan (I don't think that's the problem )

Any idea about what happens, and tests or solutions I should try ?

Thanks,
frs.

[frStudent]

I just made another test, the noise is back

Aslo, is it normal that the anode des only 3/4 of the perimeter and not all ?
Attachment 457764