Need Help!- 2 inch arc from laser tube to the chassis

[malagant]

Hi,

I just received cheap Chinese 40W CO2 laser (Shenhui Laser). It did came in perfect condition, but it's not working. Problem is this:

Laser error - YouTube

Few pictures of the laser tube:

http://lauri.jamsa.me/pic/laser/2011...2012.53.58.jpg
http://lauri.jamsa.me/pic/laser/2011...2012.53.50.jpg
http://lauri.jamsa.me/pic/laser/2011...2012.54.07.jpg

There is no loose wires on anything like that. The isolation of the high voltage wire seems to be also ok (according the pictures). Still the arc flows to the chassis. Why? And how I can fix this? Of course I have contacted the seller, but I don't want to send the machine back to China - I need to cut stuff!

[keebler303]

Ha ha, looks exciting! I am not sure it would change things but it doesn't look like you have the water cooling in place??? It could be a bad tube. If the gas micture is wrong or missing (vacuum) then you will not get emission. I'd try it with water cooling but it seems there is a problem with the tube, I have no experience with these tubes so I could be completely wrong, just my $0.02.

Matt

[malagant]

Originally Posted by keebler303 Ha ha, looks exciting! I am not sure it would change things but it doesn't look like you have the water cooling in place??? It could be a bad tube. If the gas micture is wrong or missing (vacuum) then you will not get emission. I'd try it with water cooling but it seems there is a problem with the tube, I have no experience with these tubes so I could be completely wrong, just my $0.02. Matt

Water cooling is in place

[keebler303]

Originally Posted by malagant Water cooling is in place

The water is only in the outside of the tube, not the inside, correct? The ground wire at the other end of the tube is connected to where it should be?

Matt

[malagant]

Originally Posted by keebler303 The water is only in the outside of the tube, not the inside, correct? The ground wire at the other end of the tube is connected to where it should be? Matt

I'm not sure about this. I just connected the water inlet pipe to the pump and noticed that the water is circulating properly and no leaks present. Blue wire from the other end of the tube goes to the huge resistor (10 x 2 cm), so yes, I think.

Laser tube gone bad?

[keebler303]

Like I said I've no experience with glass laser tubes, though I have experience with lasers and high voltage. I would think that the tube may be bad because the current should travel through the tube, which would present less resistance than jumping a 2 inch gap to the chassis.

Have you talked to the manufacturer? I would think others may have had similar experiences.

Matt

[Curley]

My bad idea.

[notexpert]

Malagant,

Remove the foam rubber from your machine - I think it causes your problem...

-Hannu

[malagant]

Originally Posted by notexpert Malagant, Remove the foam rubber from your machine - I think it causes your problem... -Hannu

I removed it before powering up the device. Device is new, so it might be that the problem is gas leak on the laser tube or something like that. Let's see what the seller says about that. I'll keep you posted.

[notexpert]

Double check the isolation of your wiring and add some more (for test). You could also try to clean the surface of the tube to remove any possible conductive stuff from it...

Hope you get your problem solved

-Hannu

[Exsecratio]

Tubes dead, and shortly to follow will be your power supply if you allow it to arc like that.

That arc is 22,000 volts, if the loop is across your heart on way to ground it will kill you.
Most laser tubes when they eventually die act this way.

best wishes

Dave

[Tweakie]

I just received cheap Chinese 40W CO2 laser (Shenhui Laser). It did came in perfect condition, but it's not working. Problem is this:

As has already been said - Unfortunately, that is often what happens when the tube is dead. You need a replacement tube.

Tweakie.