What do I need to make these lasers work?

[TheYellowDart]

I was recently given 3 lasers by a friend of mine. They are home made (not by my friend) and apparently require a computer to control them. I don't know much about lasers, so please bear with me. I'm sure my terminology is all over the place.

There are several components which connect together to make these lasers work. A power supply, the laser box, what looks to be a box which does parallel <-> dmx, and another box which looks like a smaller power supply but I'm not sure.

Here's a photo of the setup. On the bottom of the left stack is what I think is the DAC, the next one up is the power supply and on the top is the smaller power supply. The grey round thing in the middle is a variable transformer (does between 20 and 260 volts from a 240v source) and in the bottom-right is the box with the laser and scanners etc.



In the following two photos you'll see a close up of the power supply controls and the back of what I think is a DAC module. I'm very unsure of whether this is a DAC. The cables that came with the lasers that fit there have a parallel plug on one end and on the other is a small round threaded female plug with 9 holes of which 7 are taken up by contacts. I've never seen this plug before, nor is there any other piece of equipment with the lasers that it would plug into.



What hardware/software would I need to get these lasers running? They do work as my friend said the person he got them from hooked them up and showed them running, though he doesn't remember how they did it. I have hooked them up and turned them on, only got as far as the fans spinning up though, which is what I expected with no signal.

Is the module on the bottom of the stack a DAC? If not, what could it be? If it is, am I going to be up shit creek looking for drivers?

Which of these power supplies should I be using? They both have the same inputs/outputs and the same number of knobs/switches, except for no fan+ switch on the smaller one (and it being about 20 odd kilos lighter!).

I realise this post most likely won't have a lot of information you need to give me answers, but I know nothing at all about lasers, or lighting in general. So please bear with me, and probe me with questions to help sort it out.

Two of the lasers apparently work, the third one definately does not. This is very unfortunate as it was the coolest looking one of the lot. The glass tube, which is about 4 feet long, is broken at both ends. My friend "thinks" this was the red laser (the other two being green and blue), but he didn't seem entirely sure. I don't even know where to begin looking for a replacement. Where would I start, and what sort of costs would I be looking at?




Thanks a lot for listening to my ramblings. If anybody can help me out with anything I've asked it would be very much appreciated.

Dart

[allthatwhichis]

Wow... all I can way is welcome, and... good luck. It looks as you got a good gift or 3. I can't help you except to say this is the site where people can help... just not me.

[Laser Ben]

I can tell you that the broken tube was a Uniphase HeNe. Your best bet would be to replace it with a diode. This would be as cheap as $100.

[buffo]

First off, welcome to PhotonLexicon! Hope you like it here...

It seems you picked up quite a load of equipment there. Looks like what your friend (or the friend of your friend) had was a full color RGB system based around a high power helium neon laser and a pair of small air-cooled single-line argons. My guess is that the whole system was probably capable of 30-40 mw of red, and another 40-60 mw each of green and blue, for a total output of around 125 mw or so. Basically this was the cat's meow for a hobbyist about 10 years ago, and was about all you could do without resorting to 3 phase power and water-cooled lasers. (Which were, and still are, *really* expensive.)

Unfortunately, the really cool parts of the projector are probably going to be hidden inside the box with the large round fan sticking out of the top that you can just see on the right side of the first picture. Hopefully inside there you'll find a set of X/Y scanners, several optical mounts w/ dichros, and either 3 AOM's or 3 more scanners set up for blanking. If not, if all you've got are the lasers and the controller, then you'll need to add scanners plus some method of blanking the lasers if you want to do a show that is controlled by a computer. (Ion lasers can't be blanked by modulating their power supply like a diode laser can.)

It looks like the controller supported ILDA output via the 25-pin parallel port and also had several DMX outputs as well. Likewise, I'm betting that the computer connected to the controller via the other 25-pin port. Thus, inside the controller box you should find a parallel-port DAC, though it looks like there might be other controls that also connect to the unit. (Perhaps a hybrid controller that supports both local analog effects for live play and computer-based shows synced to music.?.)

Unfortunately, you'll need to take a lot more pictures (especially of the insides of those cases) before anyone can tell you what hardware you have, much less what sort of software it might have used. It would also help to know how the system was used. Was it set up in a nightclub or a planetarium? Was it played "live", or did it playback a pre-made show? (or both?)

Before you run off to grab your camera though, let me ask a few more questions of my own. Do you have an idea as to what you want to do with all this hardware? I mean, you sound as if you're new to lasers, and that's fine, but what was your plan when your friend gave you all this hardware? Are you a budding hobbyist that wants to get into lasers, or are you looking to set up some sort of commercial system? (Because commercial systems need to be a lot more reliable than a hobbyist system does.) Are you interested in making shows, or are you just looking to experiment with lasers and learn about them in the process? (Depending on your goal, it may be better to start with newer gear vs. trying to rebuild this older hardware.)

The HeNe is already shot, but it can easily (and cheaply) be replaced with a solid state laser. If the argon laser(s) still work you can have a lot of fun with them. However, if they don't work, you're looking at quite a bit more money to replace them. The rest of the equipment is a huge unknown. You may be able to hack it back together and get it running, but if you're not a hobbyist at heart then this may not be the best option. How long ago was the entire system last seen in full operation?

Bottom line: this appears to be some old, custom hardware. As such, it's probably going to take a good bit of tinkering to get it working like it used to. Furthermore, it's usefulness may be in question given the technology that is currently available.

By the way, where are you located? (Your profile information isn't filled out.) If you're close to one of our members here on PhotonLexicon, it's possible that someone may be willing to meet with you and have a look at your equipment. If you're in the US, (and more specifically, on the east coast), you may want to attend the South Eastern Laser Enthusiast's Meeting in Newton, North Carolina next weekend. I'm sure you'll be able to get plenty of answers there! (If you are in Europe, then you just missed a laser gathering in the UK... It was held today!)

From a hobbyist's perspective, the stack of equipment looks cool. And if you have a passion for tinkering with electronics, I'm sure you'll have a lot of fun as you work to get all that gear working again. Feel free to continue to ask questions and post pictures of your progress here. But if you're looking for a "plug-and-play" solution that will get you into lasers and laser shows quickly, I think you might end up more frustrated than anything else with this project. You may be better off scavenging some of the usefull parts from this system and using them as a basis for a new project.

Adam

[TheYellowDart]

Thanks for the responses guys, much appreciated. I'm not interested in using these lasers for commercial purposes, I just like fiddling with electronics. My friend has had them sitting in his shed for about a year. I offered to try and get them working for him and he said if I did I could have them. I wanna see what these babies can do.

These lasers were previously used in a rave environment, computer controlled and synced to music. About a year ago when my friend obtained them, he was shown both the green and blue definately working.

I've opened up the bottom module with the parallel ports and found that there is no DAC inside. From what I can tell it's nothing more than a DMX hub. Here are a couple of photos of inside the unit. The first is of the back of the ports and the second is of the other side, which has 2 rows of lamps and a latching pushbutton to either side. The third photo is of the mystery cable which has parallel on one end, and a circular plug with 9 pins on the other.



Inside one of the housings of what you guys think is an argon laser the tube is intact. The tube does, however have some discolouration on it at one end. Is this normal or would it indicate it being on its last legs/already blown? Here's a piccie, you can see the discolouration on the left.



In the other end of the box, seperated by a piece of MDF with a hole in it for the beam, you find another power supply, some static mirrors which direct the beam at two scanners. The first photo is of the power supply and mirrors, the second of the scanners.



As the power supplies both have gain/offset controls, and they are the last point before the lasers I figured I'd open them up as they may have a DAC inside them. No such luck. To my uneducated eye they pretty much only contain circuitry for rectification/regulation. What did pique my interest though in the larger one is the massive heat sink which is cooled by 2x240v fans which move a fair bit of air for their size. This can be seen in the top-left of the following photo. I've also included a photo of inside the smaller one in case anybody can see what it'd be used for. What would this heat sink be cooling? There doesn't seem to be much obviously attached to it and I can't really see inside of it.



With regards to the suggestions that the broken tube can be cheaply replaced with a solid state laser, how closely would I need to match the light output of the current laser? How would I deduce the output of the current laser? Could the electronics be reused, or would it be completely different?

That's it from me for the moment, again thanks a lot everybody who has replied, there's a steep learning curve but you're all making it much easier. Oh, I live in Sydney, Australia for those that were interested.

Dart

[stanwax]

Hi Dart and welcome
looks like a cool haul - especially for nothing!

Inside one of the housings of what you guys think is an argon laser the tube is intact. The tube does, however have some discolouration on it at one end. Is this normal or would it indicate it being on its last legs/already blown? Here's a piccie, you can see the discolouration on the left.

Yep this is an argon - if my memory serves its a NEC tube - notable for its unusual use of a glass end bell - Most argons of this size dont give you a peek inside as they are metal/ceramic/berillya. This discololuration is through use but it probably means its seen much action rather than dead - though if its got a lot of hours on it then it may be nearing end of life. But if you wanna just play around a bit it may have enough life in it for you to get a taste of the laser life

In the other end of the box, seperated by a piece of MDF with a hole in it for the beam, you find another power supply, some static mirrors which direct the beam at two scanners.

Dont know what the scanners are - but you have some and that a good start - I had quite a few lasers before I had any scanners. You may need to get them out of the box & take more pix for us to id them - or they may have some id on them. Where do the cables from the scanners go? They will need a driver card with what should be clearly visible 2 separate identical channels, then in turn this driver will need power - usually a split power supply of 20-30v at a couple of amps. The pic that you have called small power supply may be the psu & driver for the scanner. There is a psu and what looks like 2 channels maybe for manual control from the knobs on the panel. This is just a guess so check what connectors are on the scanners and see if anything matches.

To my uneducated eye they pretty much only contain circuitry for rectification/regulation. What did pique my interest though in the larger one is the massive heat sink which is cooled by 2x240v fans which move a fair bit of air for their size. This can be seen in the top-left of the following photo. I've also included a photo of inside the smaller one in case anybody can see what it'd be used for. What would this heat sink be cooling? There doesn't seem to be much obviously attached to it and I can't really see inside of it.

I think this is one of the argon laser power supplies. Argons of that size need about 80-100vdc at up to 9 amps. The black heatsink in lower left of pic has a bridge rectifier on it - for ac to dc - the big fat red and black wires feed the dc to the smoothing capacitor in lower right. The 2 resistors on the heatsink will be part of the regulator to get the volts to the right level - they will dissippate a lot of heat and so the heatsink is needed. What value of resistance do they have marked on them? Next to the heatsink is what looks like something from a light fitting - maybe a choke to provide the start pulse??? (couple of thousand volts). The big torriod may be something to do with the filament which will need 2-3vac at 20-30 amps but i would have expected to see some big wires exiting it & cant tell from the pic unless thats something at between 5 and 6 o'clock with the black insulation.

With regards to the suggestions that the broken tube can be cheaply replaced with a solid state laser, how closely would I need to match the light output of the current laser? How would I deduce the output of the current laser? Could the electronics be reused, or would it be completely different?

Its likeley that a modern diode of 100-150mw would be more than enough red to match the argon(s) - is there one or 2 argon lasers in this? - depends on thier power - so you may be able to use one and throttle it back a bit ie not use it a full power. You wont need to know that output of the current laser as such just play with the red output till it matches and makes a nice white Going on the size of the hene and the fact that henes dont tend to do much over 50mW and we have to assume it matched the green and blue it was probably 30-40mW - I think a laser diode of 100-150 would do you as most diodes will be a longer wavelength than the hene and so will need more power to appear as bright. If you can get one around 650nm is a good balance od colour and visibility. Though you could go for a 635nm which will look just like the hene - colourwise not beam wise - but be more expensive. The electronics to drive the hene will be wildly different to the diode so dont consider using this kit at all. if you buy a diode module you should get a driver with it - power on ready to go.

one final thought. The lack of any apparent blanking (unless you can provide photographic evidence to the contrary) leads me more strongly to think that the box (small power supply) does do manual controll of the scanners with some sort of oscillators to create abstract patterns. I doubt it was ever computer controlled. This is by no means a bad thing. For a starter laser if you get it going im sure you would have hours of fun.

Be warned if you get it going and do get hooked - its a slippery, expensive slope to laser utopia

Good luck and keep us informed

Rob

[dave]

Yep this is an argon - if my memory serves its a NEC tube - notable for its unusual use of a glass end bell - Most argons of this size dont give you a peek inside as they are metal/ceramic/berillya. This discololuration is through use but it probably means its seen much action rather than dead - though if its got a lot of hours on it then it may be nearing end of life. But if you wanna just play around a bit it may have enough life in it for you to get a taste of the laser life

NEC3030 i believe A local supplier at one stage had a lot of these tubes.

I think we have one kicking about somewhere as well

[Banthai]

Hi
Nice Freebies ...

The scanners are GM20s made by general scanning, although you can use them as scannners they are really suited to being Actuators, they are usually used on beam tables to deflect to gratings etc... they are quite slow and open loop so they are not possible to do grafix , but ok for simple beam shows.

hope you have plenty of time on your hands as you have got a lot to play with

all the best ... Karl

[sonaluma]

Hi Yellow Dart,

I recognise the tube and the power supply components. A few years ago, Oatley Electronics (Sydney) bought a lot of NEC 3030 argon heads removed from graphics arts printers. When argon heads get old, it is no longer simply a matter of re-gassing to restore them. The filaments and electrodes oxidise and deteriorate, the windows and mirrors need cleaning or replacing and there are other electrochemical effects. When this maintenance is not justified, the heads get removed and replaced instead of re-gassing. This is why there are many old argon heads on the surplus market, but a shortage of the original power supplies (they generally stayed in service in the printers). Oatley sold the heads with a kit of parts to build the linear power supply I see in your photos. It's heavy and inefficient compared to the original, but it should work fine.

The silver patch you see inside the tube is a gas "getter" and is part of the design, not damage. Any other junk inside the tube is probably detritis from the filament (as others have said, this is expected in a tube of this age). This tube has internal mirrors, so there is no cleaning or alignment you can do (this is both good and bad). Though the specified output power would have been 20-40mW, the tube will have had several tens of thousands of hours on it before it was removed from the printer, so even with the full filament current (about 8-10A) you can expect optical power output of about 10mW, no more. You should try and get it to lase, even if just to see the colour (single line 488nm) which is a beautiful green-blue colour that you probably won't see again.

Kind regards,

sonaluma

[Zoof]

Hi Dart,

looks like you have some nice (nostalgic) toys to play with. Be sure to check Sam's laser FAQ. It has a wealth of information about all sorts of lasers. Since you are new to lasers you can read up there so you know what you're getting into, especially safety-wise with respect to the argon laser. Take your time, there is a lot there.

Enjoy it and like mentioned before... it IS an addiction