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ArcticMyst Security by Avery

20 years old red He Ne laser < 1 mW

Joined
Aug 28, 2011
Messages
6
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0
he people,

First I want to thank you people for making such a good forum, it's great!

Lets start the story with some pics:





As the title may say, it's about an old HeNe laser. My school knows I'm into lasers and that kind of stuff so they gave me this old, weak laser. They said it isn't working properly. I took it home and tried to turn it on. It began flashing but a continuous wave wasn't coming. After I saw some smoke coming out of the transformer, I tried to turn it off using the switch. But I felt there was current running through the metal switch so I pulled out the plug. I heard a noise during the operation, like a coffee machine making coffee. Is that normal? I checked the fuse because I was asking myself why the fuse hadn't blown. It turned out to be a fuse that was 24 times stronger than the laser housing says. I bought some 250mA fuses and tried again and as I expected the fuse blew directly. That means something is wrong. What could it be? During the flashing of the laser in the beginning there was a clear red dot on the wall. Maybe I should build a new PSU because something is really wrong. What do you people think? On the first picture you can see that a few component are missing, but there is now solder so there has never been components. It's just weird. The laser has been working for about 20 years.

So guys, what do you think?
 





Joined
Sep 12, 2007
Messages
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The extra space looks to be for more filtering caps. These would only be necessary if it were a larger laser. If smoke is coming out of the transformer, the transformer is probably shorted somewhere. You might just want to replace the whole power supply. I think they run >$20.
 

honeyx

0
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Jun 12, 2011
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Yes. It will be the transformer. You either will have to replace the transformer or the whole power supply. I guess such a transformer will be hard to find these days but you might have luck and get one. Or just watch out for a complete He-Ne power supply.
 
Joined
Sep 22, 2010
Messages
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Since it's 20 years old I'm guessing either the transformer shorted or a cap somewhere failed. I'm not sure how difficult rebuilding the internal power supply would be but with a bit of work you could retrofit the tube with an external supply pretty easily. I'm not sure what you'd ned to power that tube since it's different than my tubes but I'm sure daguin or one of the other gas laser gurus will chime in too.
 
Joined
Sep 20, 2008
Messages
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Not sure where you live but the input requires 220VAC
as indicated on the label...

Jerry
 
Last edited:

Things

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Joined
May 1, 2007
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Remove the transformer, and use a multimeter on the continuity setting to see if there is a short anywhere else in the circuit.

Be sure to discharge all the capacitors first though!
 
Joined
Aug 28, 2011
Messages
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Thanks for all the reaction, but I still haven't made a decision about what I should do.

I was wondering around on YouTube and found some video's on YouTube about microwave transformers. At the
end of this video (it's a crap video sorry) this welder thing he made makes sounds just like my PSU did. Maybe it
makes things more clear if you now what the sound was like. Here is the video:


The sound starts on 1:29 and ends on 1:34. It's exactly the sound my PSU made. Maybe that means that one
particular thing in wrong. Might be helpful.
 
Joined
Sep 12, 2007
Messages
9,399
Points
113
All line-frequency transformers make that sound. Some are noisier than others. Older ones can have loose laminates that vibrate more.
 
Joined
Nov 17, 2009
Messages
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83
The anode connection might be loose, too, I suppose. Looks like there's some charring under the board around there... The "coffee maker" sound you heard was definitely arcing of some sort.

I'd say it's definitely repairable, the tube is probably fine.
 
Joined
Jul 4, 2008
Messages
2,499
Points
113
he people,

First I want to thank you people for making such a good forum, it's great!

Lets start the story with some pics:





As the title may say, it's about an old HeNe laser. My school knows I'm into lasers and that kind of stuff so they gave me this old, weak laser. They said it isn't working properly. I took it home and tried to turn it on. It began flashing but a continuous wave wasn't coming. After I saw some smoke coming out of the transformer, I tried to turn it off using the switch. But I felt there was current running through the metal switch so I pulled out the plug. I heard a noise during the operation, like a coffee machine making coffee. Is that normal? I checked the fuse because I was asking myself why the fuse hadn't blown. It turned out to be a fuse that was 24 times stronger than the laser housing says. I bought some 250mA fuses and tried again and as I expected the fuse blew directly. That means something is wrong. What could it be? During the flashing of the laser in the beginning there was a clear red dot on the wall. Maybe I should build a new PSU because something is really wrong. What do you people think? On the first picture you can see that a few component are missing, but there is now solder so there has never been components. It's just weird. The laser has been working for about 20 years.

So guys, what do you think?

You can get a mini PSU from a car neon kit ($40). They output 2-4Kvdc at about 5mA. They output pretty much the same way as a HeNe supply. I think you will have more luck than
trying to mind another specifically laser PSU. Actually I know of several people up at the University who use car neon PSUs for retro HeNe tubes. They work well. Hell, you can even make them portable too. :)
 
Joined
Aug 28, 2011
Messages
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0
he guys,

Thanks for all the reply's and the suggestions. I bought recently Lot's of laser stuff and ran kinda out of money. So that being said I'm not really interested in buying a new PSU, I'll probably check some continuity on my circuit, desolder my transformer to see if I can backtrack where the transformer is making some false connections or shorts. If I can repair it I will. If I can't I'll check first on a electronic specialist, and if that doesn't work, I almost have to bay a new transformer/PSU. But first I need to buy a desoldering pump. The poor thing is that I need to go all the way across town to buy one... It will probably be tomorrow.
 
Joined
Aug 28, 2011
Messages
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***UPDATE****​




I took off the Transformer using some improvised soldering braid. On the image with the colored pins It means the following:
red represents 'not soldered to the board'
the same color represents 'connected with each other on the board'
I placed the yellow one to make sure I knew witch side was

using the yellow sticker as reference, I think on the row with 8 pins the inner 4 pins are 720V the 4 outer pins are 18v. this powers the 'power on/off' light.

I'll be doing some measurements on the board itself to check if there are any shorts or defect components. I'll keep you up to date.
 

honeyx

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Joined
Jun 12, 2011
Messages
377
Points
28
Now we can see it clearly. It´s the transformer that got defective. The rest will be probably ok.
 
Joined
Aug 28, 2011
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On the 5th photo, the transformer looks really defective, like the whole underside have been melting away... Although it looks that way on the pictures, if I look at it with my bare eye (not on the picture) it looks real different and just a little bit of melted pieces. Is there A way I can make sure it's the transformer that's broken?
 




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