Q's about a Cyonics ArIon laser

[Hemlock Mike]

I just got a used Uniphase Cyonics Argon Ion laser from ebay. It is a model 2201-15SLB rated 25 mW single line 488 nM. Sure is a pretty sky blue color at 27.1 mW full power.

Questions: 1: Running at full power (10 Amp 120 VAC input), It shuts itself off after about 7 minutes. At half power, it pretty much stays on. Heat from the laser head fan doesn't seem too high and I have blown the head out with that canned gas stuff. Is the head over heating ?? How many sensors ??
2: I can't find a schematic on Google -- Anyone ??

Thanks -- Mike

[GreatCornholio]

I just got a used Uniphase Cyonics Argon Ion laser from ebay. It is a model 2201-15SLB rated 25 mW single line 488 nM. Sure is a pretty sky blue color at 27.1 mW full power.

Questions: 1: Running at full power (10 Amp 120 VAC input), It shuts itself off after about 7 minutes. At half power, it pretty much stays on. Heat from the laser head fan doesn't seem too high and I have blown the head out with that canned gas stuff. Is the head over heating ?? How many sensors ??
2: I can't find a schematic on Google -- Anyone ??

Thanks -- Mike

You are running into an overheat. You are very fortunate that it is shutting off instead of shutting down for good. What type/cfm of blower are you using? Is this head the cylindrical or rectangular model? I found the bigger and faster the squirrel cage fan the better off you are. A common mistake that people make with these lasers is they hook up the fans backwards. You want to attach the squirrel cage(or other type) so the fan is extracting or pulling the air out of the laser head from the front air intake vents and towards the rear of the unit. This is the way they were designed to work. Hope this helps, Cornholio

[MarioMaster]

yea you probably need a bigger fan, that dinky axial fan isn't cutting it

[Hemlock Mike]

The PS and head are about 5x5x12". The head has the round tube and I've blown out what little dust was in there. It has a 5" fan on the top drawing air in through the fins, front and rear. This fan really spins its seven blades -- Loud !!
The PS has a 3' fan, quieter drawing air from rear to front. It doesn't seem to get hot.
I think the head is what's getting too warm and reading on SAM's indicates that you shouldn't run these at full 10 amp current very long.
That's what I have so far.
Thanks ----
Mike

[Hemlock Mike]

More info -- I cleaned it some more and replaced all the missing screws in the housings. The hour meter shows 7500 Hours !!! I've now run it for about 30 minutes at increasing power from 10 mW to 18 mW without shutdown. Heat from the laser head is warmest but not hot.
Yes it will pop a balloon using a focusing lens at 12 mW out.
I'd still like to find a schematic.
Mike

[buffo]

If you replace that fan on top of the head with something that moves more air, you might be able to run the head continuously at 10 amps without it shutting down on overtemp. However, as mentioned in the laser FAQ, running at 10 amps is not good for your tube life. Since it's already got 7000 + hours on it, you don't want to push it. Better to run it down around 6 amps.

Adam

[mliptack]

Just out of curiosity (since I am from a younger generation ) I have never actually had the chance to play with a gas laser (I remember being amazed by laser pointers in middle school - when red diodes came readily available for $100+/each) could one rig up a better heat exchanger for something like this?

What type of temperature stability do you need? Is colder always better? Once the laser has actually started to laze could you bring it to much lower temps like 40degF or below freezing?

I think I have already come to the conclusion that I will stick to diode lasers and maybe some rod style lasers. But it never hurts to build my knowledge on other lasers

-Max

[Hemlock Mike]

Mlip ---

I'm new to ion lasers myself. I was building CO2 lasers 35 years ago using plans from Scientific American!
The Ion lasers have a hot Cathode with filament like old vaccuum tubes. Temperature will also have some effect on tube pressure. I'm still learning too - that's why I would like a schematic or manual on this laser.

Mike

[mliptack]

So I bet the operating temperature, could only go so low as to not let the temp of the cathode go past a critical point. If that makes sense.

-Max

[buffo]

could one rig up a better heat exchanger for something like this? <snip> Is colder always better? Once the laser has actually started to laze could you bring it to much lower temps like 40degF or below freezing?

You can rig up better heat exchangers, but it's expensive. You can't just dunk the thing in a tank of water though. There's a section in the laser FAQ where someone tried that. The seals on the tube failed in about an hour.

I believe you *could* submerge it in Fluorinert and then pump that through a radiator (or even a water-cooled heat exchanger) to remove the heat. But the stuff is fantastically expensive. I've seen it listed for over $900 per gallon!

Then too, colder is not always better. You want it to be cool, but not freezing cold. Temperature will change the gas pressure in the tube, which can cause problems if you go too low. Plus you still need to keep the cathode filament hot.

And finally no matter how cold you get the tube, on smaller lasers like the SP 163, or the Cyonics Uniphase 2201, or the ALC-60X, you're going to reach a gain saturation point where no matter how much more power you send down the bore the output won't increase anymore. (This is also covered in the laser FAQ in greater detail.)

Adam