[jbarber]

I have a 50W tabletop laser that quit firing right in the middle of a job last night. No warning, it just quit firing. The controller kept right on going, but no output from the tube.

I can hear a "ticking" sound from the power supply when the tube should be switching on, if that's of any use. The tube doesn't light at all, and a piece of tape over the first mirror stays clear when I use the controller to pulse or use the TEST button on the power supply.
The coolant temp was at 96F, and after it quit I examined the tube carefully. No cracks or coolant in the outside envelope, everything looks fine.

So... since the tube "looks" fine and I have no other means to test a 20KV power supply, I ordered a power supply. Any guesses as to whether that was the right choice? If it turns out to be the tube I'd rather have one coming than waiting another 7-10 days...

Thanks,
--jim

[AlexTsekenis]

If I had to bet I would say it's the power supply. The ticking sound would probably be a circuit energising the high voltage transformer; a process then immediately stopped by some safety sub-circuit inside the power supply. This is called 'hiccup' mode, where the power supply tries to recover from something. It could be that. Good luck with the new PSU.

Alex

[Louis_Cannell]

to check power supply try the following with care.

one packing bean polystyrene or PVA type tied to a long piece of cotton. suspend over to the side of the wire connected at back end of tube and fire the laser.. If HV is there and power sup[ply is working the peanut will move towards the HV.

[Dean448]

96 deg f is to high. You should stay between 15 and 20 deg C.


Sent from my iPhone using Tapatalk

[Louis_Cannell]

96 deg f is to high. You should stay between 15 and 20 deg C.

Agreed to maintain gasses and catalysts should be operated below 72 deg f, so likely the tube is not likely to last long under these conditions a few hours can kill the tube.

[laser82]

Jbarber this sounds similar to my problem , did a new power supply fix the problem?

cheers pete

[aussiemate]

I have a 50W tabletop laser that quit firing right in the middle of a job last night. No warning, it just quit firing. The controller kept right on going, but no output from the tube.

I can hear a "ticking" sound from the power supply when the tube should be switching on, if that's of any use. The tube doesn't light at all, and a piece of tape over the first mirror stays clear when I use the controller to pulse or use the TEST button on the power supply.
The coolant temp was at 96F, and after it quit I examined the tube carefully. No cracks or coolant in the outside envelope, everything looks fine.

So... since the tube "looks" fine and I have no other means to test a 20KV power supply, I ordered a power supply. Any guesses as to whether that was the right choice? If it turns out to be the tube I'd rather have one coming than waiting another 7-10 days...

Thanks,
--jim

Hi Jim

What ended up being the issue for you here?

[jbarber]

Hi Jim

What ended up being the issue for you here?

It was a power supply failure.

To make it worse, (or perhaps funnier) I ended up upgrading the tube and power supply to 60W, which required adding an extension "can" to the side of the cabinet.
It ran for a few hours, then the 60W power supply quit. I replaced it, and the 2nd power supply ran an hour or so then quit.
This time, it turned out the new 60W tube was arcing over internally and causing the power supplies to fail. I replaced both the tube and the power supply, and it's been fine since.

I seem to attract that kind of thing...

--jim

[aussiemate]

Thanks Jim. I'm worried ours is doing the same as I've lost another motor and can't fire the tube unless pressing the test fire button on mine.

Do you mind explaining how the tube was arcing over internally? What symptoms did you see you diagnose this?

[aussiemate]

It was a power supply failure.

To make it worse, (or perhaps funnier) I ended up upgrading the tube and power supply to 60W, which required adding an extension "can" to the side of the cabinet.
It ran for a few hours, then the 60W power supply quit. I replaced it, and the 2nd power supply ran an hour or so then quit.
This time, it turned out the new 60W tube was arcing over internally and causing the power supplies to fail. I replaced both the tube and the power supply, and it's been fine since.

I seem to attract that kind of thing...

--jim

Thanks Jim. I'm worried ours is doing the same as I've lost another motor and can't fire the tube unless pressing the test fire button on mine.

Do you mind explaining how the tube was arcing over internally? What symptoms did you see you diagnose this?

[jbarber]

I’m not sure how losing a motor and a faulty tube would be related, but in my case you could hear a very high-pitched squeal that would increase in intensity with power, and there was a white corona when the tube was running. You could see it in the tube a few inches back from the business end. I have no idea how or why it started. A friend suggested a leak between the water jacket and the gas tube, but if that were true the coolant woujld have leaked into the gas tube and it would have never worked at all. As it was, the tube ended up being pistol fodder since the vendor was convinced I had damaged it somehow and wouldn’t replace it.

Given your description, I’ll speculate your situation might be more likely to be controller failure rather than the tube. Again, I can’t correlate a faulty tube with motion control issues.

... but what do I know? I’m Murphy’s favorite nephew, it seems.

—Jim

[aussiemate]

I’m not sure how losing a motor and a faulty tube would be related, but in my case you could hear a very high-pitched squeal that would increase in intensity with power, and there was a white corona when the tube was running. You could see it in the tube a few inches back from the business end. I have no idea how or why it started. A friend suggested a leak between the water jacket and the gas tube, but if that were true the coolant woujld have leaked into the gas tube and it would have never worked at all. As it was, the tube ended up being pistol fodder since the vendor was convinced I had damaged it somehow and wouldn’t replace it.

Given your description, I’ll speculate your situation might be more likely to be controller failure rather than the tube. Again, I can’t correlate a faulty tube with motion control issues.

... but what do I know? I’m Murphy’s favorite nephew, it seems.

—Jim

Ah sorry if I've confused you about our issue.
We have a brand new motor in the laser and it still wont fire. The laser tube is new, but I did break the water tube end of it and repaired it by inserting pvc tubing and silicone.

We have tried a new high voltage power control board but that didn't fix it, nor did the new power supply.

Is the CO2 in the outer layer of the laser tube? If so, I'm wondering if the CO2 has leaked out where the glass end connection broke deep enough to leak out all the co2. - water wouldn't go in there as i inserted the pvc tubing inside the whole.

I'll put the old laser tube back in and this will at least eliminate the new (and repaired) laser tube