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Thread: First Argon

  1. #1
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    Default First Argon

    So I just picked up that ALC 60X that was on ebay
    http://www.photonlexicon.com/forums/viewtopic.php?t=761

    and talked about here

    http://cgi.ebay.com/ws/eBayISAPI.dll...m=300046957832

    Is there anything you guys can tell me before I power this thing up? I have a 4 day weekend coming up and this is the new toy

    The only real problem is blanking: You'll need an AOM (Acoustic-Optical Modulator) in order to blank it. (You can't modulate the power supply like you do with a diode or DPSS laser.) AOM's are available on the surplus market - read: E-bay - for around $100. They use an RF signal to set up a standing wave inside a crystal, which refracts the laser beam slightly. By switching the RF on and off you can alter the beam path ever so slightly - just enough to get it to pass through a pinhole and continue to the rest of the projector or to be blocked by the metal around the hole. They are *very* fast, but they can be tricky to set up and align. They work quite well, however.
    Yeah but where do I get the RF generator?


    To tell you the truth, if I were going to put a 60 X into a projector, I'd probably just put a slow set of scanners in there (15Kpps) and then add some solenoids in front of the galvo's to pick the beam off and sent it to various diffraction grating effects. I'd only use it for beam shows though... But that's just me.
    That's exactly what I want to do :-D


    One more before I go. I have an EasyLase it supports TTL beam switches. Can Mamba Use the TTL beam switches? I saw some doc on how to write a driver to use the TTL in Mamba but can't find out how to use it in a show?
    Thanks
    Myron

  2. #2
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    Default

    and talked about here

    http://cgi.ebay.com/ws/eBayISAPI.dll...m=300046957832

    Is there anything you guys can tell me before I power this thing up? I have a 4 day weekend coming up and this is the new toy
    Did you get the one from the ebay auction? Judging from the photo, it looks like the light feedback has been removed. Which isn't a problem with laser shows except that you will not want to attach the head to a p/s that runs only in light mode. This also means that the power adjust knob on the head will not work either unless it has been rewired in such a way to fool the p/s. If it hasn't been run in a while (over a year) it may be a bit hard to start. There are a couple tricks to get it going. A hand held telsa coil works very well for this. Once you get it running, let it run for a few hours at around 5-6 amps tube current. Also, one trick to determine how much life it has left in it, when you have it running and warmed up, crank up the current to max real quick (within 1 sec.) If it winks out, it may be a high mileage tube.

    Yeah but where do I get the RF generator?
    You will want to wait till you find an AOM with a matching driver. That way all you need to do is power the aom and send it a blanking signal. If you are wanting to do beam shows with this, I would not recommend an AOM as you will loose a substantial amount of power. For beam shows, and slow 12K to 15k scanning, why not use mechanical blanking? That way you loose little to no power. There are two ways you can do this, optical leverage blanking and flag blanking. You will loose very little power with the optical leverage blanking and it can be tricky to align. With flag blanking, you will loose no power and it is very simple to setup.

    David

  3. #3
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    Thanks I think mechanical is the way to go with this guy. In fact could I use this?
    http://cgi.ebay.com/Laser-beam-posit...QQcmdZViewItem

    I have 2 of them. But some how seems a bit too easy.

  4. #4
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    You shouldn't have any problems firing it up. The seller had it lasing while the auction was still going on. (The pics that were added later on - the ones showing the laser refracting off a CD-rom - were pics that the seller set up and took AFTER I e-mailed him about the original listing. So you know the thing was lasing less than a week ago.)

    The only thing you might have to deal with is the possibility of the mirrors being knocked out of alignment by the shipping. (If this happens, there is a section in the laser FAQ that deals with the 60X heads, including how to align one.)

    Make damn sure you have the fan hooked up and running before you light the tube. You can fire a 60X for short periods (10- 20 seconds or so) without a fan, but much longer than that and you run the risk of ruining the tube. If the fan ever stops, shut the whole thing off.

    The first time you light it up, go ahead and let it run for a solid hour - preferably 2 - at medium current. Since it doesn't look like the PSU has a tube current meter, you'll need to look in the laser faq to see where you can plug your multi-meter into the head... (I'm not familiar enough with the 60X head to tell you which jacks to use, or what the conversion factor is.) There should be a way that you can indirectly measure the tube current via the taps on the head. Usually you'll take a reading in volts and multiply by some factor to get amps.

    *DON'T* try to wire a meter directly in-line with the tube! The multi-KV starting pulse will fry it! Likewise, don't try to measure the tube current until AFTER the tube is lit. The starting pulse is deadly to just about any meter not rated for 10KV or so. Always use a battery-powered multi-meter to be safe.

    Care and maintenance: Once every 2-4 weeks, hook it up and light the tube. Run it at meduim current for at least 1 hour, then drop back to idle current and shut off. Do this religiously and you shouldn't have any problems. Forget to do it for 6 - 12 months, and you *will* have problems getting it started again.

    RE: Blanking... You can usually find AOM's together with the RF driver on E-bay. If not, you can look up the specs on the manufacturer's website and use that as a guide to help you build your own. (For example, the Isomet 1201-C's that I have need 80Mhz at around 3 watts to function.) This assumes that you're not afraid of a soldering iron, that is.

    The mechanical blanking idea will also work, though it means you'll need to buy a third galvo (and an amp) to set it up.

    However, if you're only going to do 12-15Kpps beams with it anyway, you might want to just set it up with no blanking at all first and see how you like it. I've seen a few projectors running without blanking, and they honestly don't look all that bad. You can always add a third blanking galvo (or an AOM) later on.

    Adam

  5. #5
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    Quote Originally Posted by DjDevNull
    Thanks I think mechanical is the way to go with this guy. In fact could I use this?
    http://cgi.ebay.com/Laser-beam-posit...QQcmdZViewItem I have 2 of them. But some how seems a bit too easy.
    Those units are probably going to be too slow for laser show use. The resonant frequency is just 24 Hz! That's at least an order of magnitude too slow. Probably more like two orders of magnitude too slow.

    What scanners are you planning to use for the projector? Can you get a third one?

    Adam

  6. #6
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    I just wanted to use that guy for blinking. I first got these for the idea of making them a cheap beam switch. I think I got them for $12 almost a year ago.

    Currently I'm using the 15k from Dave in my main projector. I plan on getting the 40k ones. Putting the new ones on the main and using my current ones for the argon.

  7. #7
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    Ok - I see what you mean. If you want to use them as shutters to select various beam effects (diffraction gratings, etc) in your projector, then yeah, they should work just fine. (I thought you were going to use them as a 3rd galvo for blanking.)

    As shutters, they should be at least as fast as a rotary solenoid is... Maybe a tad faster even. So yeah, they should be fine.

    Come to think of it, it would be cool to have a few of those to play with. I see from the auction that the guy is selling a lot of 100 of those things. Wonder if he'd make us a deal to sell just 5 or 10?

    Adam

  8. #8
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    he sells them single too not just lots.. and I got mine from him cheap cheap

  9. #9
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    You shouldn't have any problems firing it up. The seller had it lasing while the auction was still going on. (The pics that were added later on - the ones showing the laser refracting off a CD-rom - were pics that the seller set up and took AFTER I e-mailed him about the original listing. So you know the thing was lasing less than a week ago.)
    Thats not always true with a 60x. I've had a 60x with a high mileage tube and at times, to get it started was quite a problem. Sometimes take an hour to finally get it to maintain discharge. In fact, when I first got it, I figured it was just high pressure, after getting it started with a tesla coil, I let it run all day. Then it would sometimes start on the first start pulse, sometimes it would just wink for 15 to 20 minutes before finally staying lit. once lit, it would run great, output was around 50 to 60mW with about 7-8 lines. The quickest way that I found to see if a head is good or not, was to ramp up the current quickly after warmup, if it winked out, then I would consider it nearly gassed out. The ones that would not wink out, seemed to be the most reliable and would always start on the first pulse.

    David

  10. #10
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    Good advice Dave. However, I'm fairly certain that Myron will be OK in the case of this specific laser.

    I spoke with the seller of this laser (via e-mail) several times. He has owned it since 2001 and by and large he's taken good care of it. Although he admitted that he didn't always fire it up every month, he did use it enough that it starts just as quickly as it did when he bought it. Never, ever exhibited any signs of hard starting. (I actually considered bidding on this auction myself, based on my conversations with the seller.)

    The head and PSU were both manufactured in 1995, so compared to some of the 60X units out there, this one is relatively new. (I've got a Spectra-Physics unit that is 10 years older, and it still works just fine...) Likewise, the seller hooked up the laser and fired it at least TWICE while the auction was in progress, again with no problems.

    Now, I grant you that the tube could still be near end-of-life. However, if you look at the pictures he posted, you'l see that the tube is still making 5 lines. That tells me that the tube still has *some* life left. (Though it would be prudent to do the rapid power-up test as you mentioned just to be sure.)

    Adam

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