Arcing inside CO2 tube

Hello everyone, this is the second time in a very short time that this has happened to me, the tubes are from the same supplier.

Is it just that the tubes are poor quality or could it be the power supply?

The first tube ended up with a hole where you can see the arcs. I’ve had this laser for a few years now, and I replaced the original tube with a cloudray, which lasted well.

Then I bought these cheap tubes (70 Euros) and this is the second one I’ve had in less than 30 hours of work. What do you think of them? Thanks for your advice

Order another tube, this time from Cloud Ray…

A dc excited machine requires high voltage to lase, that voltage keeps going higher if it isn’t loaded by the tube lasing. When the tube doesn’t lase, the voltage climbs to higher than the weakest link in the system and discharges through the path of least inductance, usually to the machines ground or chassis.

Every tube manufacturers has tubes that don’t make specifications, especially for this type of device… known as grade B tubes.

There are not thrown out, they are discarded through the the grade B market, recouping some of the costs. People resell them or put them in low cost Chinese laser machines.

Hate to say you get what you pay for, but I think it applies here … as you purchased it from them because of price… These people have made their money off me and you, selling grade B (or worse) tubes as new, which they are … just not working within specifications. So it’s working for them, I guess…

They seem to be smiling all the way to the bank. :heavy_dollar_sign:

Good luck



That’s what you get for cutting corners … I ordered a tube from cloudray, three times the price but I hope it will work well again. Hopefully it’s just the tube.
I checked the connections, the negative wire is ok, everything is well grounded, the machine even has its own ground rod in addition to the ground of my house.
I’ve redone the high-voltage connection, bypassed the milliamp meter, but it’s the same thing…
I’m waiting for the new tube

Curious: why bypassed the milliammeter?

I bypassed the milliampere meter because I thought it might be defective and no longer let the current through, so the negative wire was directly connected to the power supply. This took a variable out of the equation.

My hv meter came into question and it’s a 50uA meter, but it was about 7k in resistance, so I added a 10k and just touched it… it showed me it wasn’t open… so no need to suspect it…

Good luck on the replacement…


Ah, OK. Diagnostic measure, not a permanent change. :+1: