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ArcticMyst Security by Avery

Got a Gas laser, Not sure how to power it.

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Seidweise

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A few days ago i got a Spectra-Physics 088 from a HAM enthusiast on where i live, he claims it works, according to the person he bought it from many years ago. according to what ive searched, its a HeNe but please correct me if i am wrong. It and seems to have some sort of either power supply or driver attached to it. I'm new to lasers in general, especially gas lasers. According to what is written on the case, its supposedly supposed to be supplied with 18v DC, but im not entirely sure the amount of current i would use, or how this thing attached to it works. The white cylender has a pot on it, but again im not sure how it works. if anyone has any info that would be awesome
cIH7dyil.jpg
 
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bdgreenb

bdgreenb

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the one on the left looks like an hene tube, thats an alden cable connecting the 2, the white thing on the right must hold the power supply, can you open it? If that's the case you don't have to worry about current, since that's its job.
 
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Things

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That red and black wire coming out the back towards you, I assume would be the power input. Try connecting them to 5V, 12V etc progressively and see if it does anything. Better to start at a lower voltage in case the label might just be misplaced, as 18V is kind of an odd voltage.
 
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Seidweise

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Cant open the White thing, and its not AC i can tell that much. As i said it supposedly takes 18v, but past that i know nothing, would just an 18v bench supply work?
 
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Seidweise

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@things
Alright ill try that


Also, Will moving the potentiometer be any help when putting current through it?
 
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Seidweise

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Also, as a PSU, would a computer PSU 5v, 12v, and then series a 5 and 12v rail for 17v work?
 
Jimmymcjimthejim

Jimmymcjimthejim

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The potentiometer on the white power supply is used to tune the amount of voltage passing through the HeNe tube. Most likely it's been tuned already for that specific HeNe tube. I really wouldn't touch it unless 18V does not power up the tube.
 
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Seidweise

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well i touched it just a little, seemed to be either all the way on, or all the way off. but ill definately be careful
 
Cyparagon

Cyparagon

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Seidweise said:
Also, as a PSU, would a computer PSU 5v, 12v, and then series a 5 and 12v rail for 17v work?
Click to expand...

No, because they both have the same ground.

Jimmymcjimthejim said:
The potentiometer on the white power supply is used to tune the amount of voltage passing through the HeNe tube.
Click to expand...

Are you sure it's not current? I don't think you can adjust the tube voltage reliably. Especially when there is a ballast resistor. In any case, voltage doesn't pass through things, current does.
 
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Things

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I'd just leave the potentiometer. If you apply power and nothing happens, then try fiddling with it a bit, but there shouldn't be any need to touch it otherwise.

Cyparagon is right, gas lasers basically have negative resistance in operation, it'd probably adjust the current.
 
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mojo_1234

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Hi,

the small pots on a typical HeNe are used to adjust the current and not voltage. Also current can't be changed from zero to maximum (only between some design limits e.g. from 3.5mA to 5.5mA).

Would just power the PSU and check what happens. The tube should at least start the ignition (using a voltage multiplier) at around 8 to 12kV (depending on tube length). This is clearly visible (tube flickers) and you'll hear some zapping noise.

And always check if there's a ballast resistor (wire, ~75k). It's absolutely neccessary (only very very small tube don't have one).

Good luck :)

and always be careful and shorten the HV cables before touching the tube --> high voltage (even a HeNe PSU might not cause sudden death it really really hurts!)

-mo-




(as most HeNe supplies are current regulated power supplies). So, in general no need to change something.
 
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Seidweise

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@Mojo
What would the ballast resistor wire look like? All the wires that are in the picture are the only wires on the unit, that I can get to without breaking open that white tube.

And how would I short the tube? Just get a piece of wire and touch the ends of the red an black wires while wearing insulated gloves?
 
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Cyparagon

Cyparagon

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Yes, that shorting method would work, or you could just use an insulated wire.

The ballast resistor will look something like this, but with different colored bands:

images


I don't see one in your picture, but it may be out of frame or inside the power supply.
 
Cyparagon

Cyparagon

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That's possible. But get one and put it in series with the tube anyway. It won't hurt anything to try.
 
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Seidweise

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I cant seem to get it to ignite, Though i may have a Bad power brick. If the brick isnt bad, then is the tube or the voltage multiplier more likely to be the culprit?
 
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