No laser output, even after power supply change!

[polarstones]

I've been using a 40W laser engraver for a few years now, and it's been fantastic...until a couple of weeks ago, when it simply stopped lasing. There is no glow in the tube whatsoever, and nothing registering on the ammeter when I try to fire. Same issue with both my 'test fire' button as well as trying through a normal program (using MoshiDraw). I have checked all the switches, potentiometer, and as much wiring as I can. I've now replaced the power board, and still no laser output! My next step is to replace the tube, but based on things I've read, the tube should have faded out, rather than just given up completely and suddenly. The MoshiDraw board seems to be functioning, and an LED that indicates when the laser is commanded to fire lights up just fine, just simply no actual beam.

Any other thoughts anyone might have would be greatly appreciated. I don't have the high voltage test gear to check if I'm getting voltage across the tube, but hopefully switching the tube will rule that out as a possible cause.

Thanks,
Stephen

[Tech_Marco]

The tube could be gone. "a few years" actually means a lot to a laser tube. Most laser tube won't last over 3yrs. Small laser tube may last 6months to 12months while bigger tube like 80W~100W may last 1~2yrs. But it all depends how you used the tube and the maintenance.

Another possible is a dead power supply. You can test it by this way and I called "shock way". I turned on the laser power supply (hear fan On). Then, I disconnected the AC power for the laser power supply. I then fire the laser with some charge remaining in the laser power supply. After that, most charge will be discharged but not totally. This time, I'll placed a screw driver with a plastic handle to touch the High voltage terminal. You may seem a little spark and hear a little sparking noise as well. That mean, the laser power supply is 90% working. Or, at least it work to some extended.

It is not the best way but it works pretty good to me. You may not want to try this way and I hold no responsibility for anyone trying to do so and got electrical shock. Remember that it is just 'my' way and it may not for you.

Marco