Laser not working

[Jim Dornon]

:mad: Hey everyone I am haveing a heck of a time with my new Chinese laser. When I first received the machine everything worked. The second time I used it the power supply over heated and blew due to one of the internal fans not plugged in(inside the power supply). After a month and a half I received a new power supply but is was from a different manufacturer due to a rash of bad power supply's. Anyway everything back together the laser tube is firing but does not come out of the tube.weird, way weird. Has anyone ever heard of this ? The laser is firing but not coming out of the tube. Any help would be great. Jim

[pete hagan]

A little more info would help here.
Who makes it / model / wattage etc...
Any pics to illustrate the issue. If the tube "glows" then there is radiation emitted but you will not see the beam unless you have very different eyes than mine. Have you held a piece of cardboard in front of the tube aperture to see if it heats up / burns?
Any additional info and possible that someone can at least give a starting point.

Pete

[Tom Cullen]

I agree with Pete, you should do the cardboard test first ( be very careful ) tape the cardboard to a piece of wood or just use thin wood that you can hold away from the beam, Also have some one help you fire the laser. Another thing you might want to check is the mirror alignment, you could have accidental knocked one out of place.

[Tom Cullen]

Just an after thought , I would only look at the mirrors if the beam fires and does not reach the table top.

[Jim Dornon]

Hey pete and tom. It is the rabbit 6090sc 60 watt. I can see the laser firing inside the tube(purple). I have tried the cardboard . The laser will not exit the tube. You can see the beam when it reaches the end of the tube arking on the metal at the end inside the tube. Very strange, frank has never heard of this. He is trying to help but not much luck.

[Joe Pelonio]

Perhaps the new power supply is faulty or not providing enough power to the tube?

I don't know how a power supply failure could cause the tube to burn out, but power supplies have been know to be bad from the factory.

[Darren Null]

I don't know if this'll help:
http://www.sawmillcreek.org/showthread.php?t=65590
Similar symptoms.

I can't explain the arcing...if you can see it it's not what you want. The beam you're after is invisible. And I'd be quite cautious about looking at it arcing from the side, if I were you- The beam can blind you in about half your blink time...on my poxy laser (10W) with a specular reflection. You have goggles, yes? Wear them. The rest of you'll heal.

Hoick the laser casing off and see if anything has exploded. Worth a look, anyway.

[Darren Null]

I found this on my travels:

But….! On day (9-19-2006) during normal operation (I am just making a sample on acrylic), I notes that there was no laser beam at the material surface but there was a laser beam inside the laser tube, so I thought that the cause may be from the mirrors , but after short checking I found that the cooling ring at the output coupler was separated from the tube end.
I contacted redsail, they told me just glue that part, I glue it but…. No laser came out from the tube. After long negotiations using web cam to show the problem, they decide to send me a new free laser tube as a warranty, with a set of optics as a gift, but I must pay for shipping by DHL.
Similar symptoms, Chinese laser. Hope that helps.

EDIT: Was posted by "Roberto_Trilogy" about 4/5 down the page, to help you find it.

[Jim Dornon]

WFrank spoke to the engineer last night and we seem to think it is a grounding problem. That would explain the arcing at the cooling ring. short to ground. Will try tommorow morning as i am at work today. Let you all know soon. Thanks for all the help so far. Jim

[Neal Schlee]

Jim,
It's possible this could an output mirror alignment problem on the tube, but if I'm not mistaken the chinese glass lasers do not have adjustable mirrors.

After changing mirrors on flowing co2 lasers for years, if the mirrors are not perfectly aligned the tube will fire but you won't get output. We've literally spent 8-10 hours getting a tube realigned close enough to output after mirror replacement on 100 watt Apollo's.
Glass tube laser's are notorius for alignment fluxuations caused by temperature changes etc. Even bumping or handling the tube can even cause alignment problems. Metal tubes eliminate 95% of these issues, I've got a 100 watt Synrad that was purchased new in '95, has at least 20,000 hours on it and has never been touched, and it still outputs 70 watts.

Neal

[Jim Dornon]

Thanks for the info. Laser was working fine until the power supply blew. I replaced it with another power supply but not the same as the old. Frank assures me it will work as it does on another model of the same brand. I did change the laser tube out with my new spare. same exact results. Let you all know soon. Jim

[pete hagan]

Are you SURE that the tube is oriented in the correct direction? LOOKING FROM BACK SIDE OF THE MACHINE TOWARDS FRONT The exit path of the laser tube should be pointed to the right of the housing (where the first mirror is located). The coiled glass tubes inside the main tube will be on the LEFT side.

I know it's a dumb question but hey my wife couln't make the vacuum work one day....it wasn't plugged in......

Pete

[Judith Halliday]

"Chinese"

Nuff said.

[Jim Dornon]

Thanks for the sarcasm Judith. Can't afford a US laser. Still not working.about to give up. Rabbit laser not much help. Would anyone like to buy it ? I am sure someone else can figure it out.

[Mike Hood]

Sorry it's not working out Jim. Despite the sarcasm... many of us have Chinese (or Taiwanese) manufactured laser systems. But... they are supplied with US-Made all metal tubes. Hard to tell what might be going wrong, but hang in there. Perhaps someone can give you more help to get you going again.

[Jim Dornon]

Well after finding a loose connection the laser fires but very very weak. It will only burn the first layer of cardboard. Pretty weak. Any ideas :eek: Jim

[Jim Dornon]

I got the laser working, sort of. Found a bad connection at the power supply. Laser will fire out of the tube now but very very weak. Will only mark first layer of cardboard. Any ideas ? Jim

[Jim Dornon]

Well, the factory is going to send me another new power supply and I think a new control card. We'll see what happens. :eek:

[Darren Null]

Very best of luck to you. I hope the new bits do it for you.