Laser tube broke

[natsterrr]

Hi,

I've had my cheap chinese machine for nearly 2 years and have been mostly engraving with it a few times a month throughout this time with no major problems.

Tonight while i was trying to cut through 2mm perspex (after engraving a few other pieces) I heard a super-loud screech and quickly flicked the machine straight off. After a few minutes I turned it back on and the laser would not cut.

I looked at the laser tube and the entire tube was filled with water!

So I guess I cracked something inside - there was no leaking from the tube into the machine.

My questions are:
- Is this normal wear and tear? I usually have to rotate the tube a little to clear the bubbles each time I fire up the water pump, but I didn't clear the bubbles out like this for the first few months until Waltfl commented about bubbles on here.

- Will any other components be damaged? I'm hoping I don't need to buy a new power supply - the DSP was fine when I tried to run it again, and switching the laser on and off while cutting, there was a definite change in sound (very faint hum while trying to fire laser) so I'm assuming all the driver hardware is still working. Im just hoping I won't need to pay shipping twice if I replace the tube and it doesn't work.

- What other parts should be changed - mirrors (what size/type?), lenses (size/type?) etc?

Thanks in advance for any help you can offer.

Natsterrr.

[NickWL]

FWIW I've never rotated my tube before use - though I do run the pumps for a minute or two (at least) before firing up.

[natsterrr]

Ok, so I ordered a new laser tube from a local seller on ebay (as light object don't ship laser tubes to australia). I rigged it up and got the water flowing through it for a while and cleared out all the bubbles. Now during this process I also took out my blue light up ammeter (which never displayed the correct amp reading anyway) and replaced it with the original analogue one, wired in series with the blue wire coming from the laser output end. Everything else was the same.

Now when I turned the power on to my machine, the laser was ON and seemed to be super high power... There was a red glow around where the laser was hitting a sacrificial test piece of perspex on my laser bed. I'm assuming this is bad for the tube...?

I have a small on/off push button switch hooked into my PWM supply where the water cut-off switch should be - this would normally allow me to control the laser on off - for example to run a program without the laser and see if it will engrave in the right position on my work piece before I re-start it with the laser power on.
This switch was doing NOTHING - the laser was just on permanently.

THis leads me to believe that the PWM supply is broken as well.

I'm just wondering (marco) if this is a common problem with laser tubes cracking and allowing water to escape into other parts of the tube, and does the PWM power supply have a safety cut-out or fuse which I can replace? Or is the whole thing fried? I bought this PWM supply from light object as my original unit was not a PWM.

And, if I buy a new PWM supply, how can I be sure that this is the problem? What if it is the DSP or something else.

Hopefully I haven't just fried my new laser tube, but it was only on for 3 short tests of about 3 seconds each, and water was constantly flowing through it.

Any answers or advice would be greatly appreciated!

[Tech_Marco]

You need to show connection. When you said red grow, inside the tube or where? Better to post some pictures


Marco

[natsterrr]

You need to show connection. When you said red grow, inside the tube or where? Better to post some pictures


Marco

I've just got it working again. It turns out that the red glow was a reflection of the orange coloured perspex I had as my sacraficial bed.

I bought a new (cheaper) power supply off ebay and it works perfectly now.
The light object power supply must have been fried when the water jacket cracked in the laser tube. Seems like a common problem, so I'm wondering why there is no cut-out or fuse to protect the power supply from such damage?

Also, the new power supply is much better than the light object one - with the light object one, I could only get the laser to fire above 30% power, so I didn't have much control over the power settings. When I bought the light object power supply it would keep the laser on a little bit while idle - very dangerous! Marco told me to fix it by winding out a screw on one of the potentiometers. Not sure if I did this right or not, but it never really worked properly it seems.

Marco, is the light object power supply covered by any warranty? and if so, where can I send my one to be repaired and tested? If I could get it back working properly it would be great to have as an emergency back-up.

I'm in Sydney, Australia.