Anyone got some info?

[Things]

I just picked up a GLG3078 argon head for the price of shipping, but the seller says he does not have much info on the laser. He said he tried contacting the company, but they said in Engrish "We do not sell in US". They do not come with a PSU, so I am looking into some details on maybe building one, since I think my chances of buying one are pretty slim. The head has all the voltage ratings etc on there, so I'm not in the dark about what it needs, but I'm not real clued in on PSU design for these things.

I haven't got the laser yet, but thought I would start searching around for any info I may be able to gather on it. Being my first gas laser ever, I'm looking forward to being able to work with one, should be a fun project

Cheers,
Dan

[RedlumX]

I have built a PSU for argon lasers some while ago, it was a fun and rewarding exercise, for info see http://pagesperso-orange.fr/redlum.xohp/switchmode.html

[Things]

Thanks for the link

I think for my first power supply I'm going to keep it simple. I am thinking about just using a microwave transformer to give me about 90VAC, then using a rectifier and maybe 20,000uF of filter caps to give me DC, then using some sort of voltage regulator/opamp passbank to regulate the current.

EDIT: OK, I have come up with a simple PSU idea.

Basically, I will be rewinding a MOT for somewhere between 70 and 100V, which will feed a rectifier, which will be filtered by a 100V, 10,000uF capacitor, which will then feed this linear passbank:



Total cost: ~$150AUD for everything but the transformer and the enclosure

Drew up a schematic:



I should ask, how does one trigger the igniter? The igniter board is included with the head and in the same box, but I'm not sure as to how you trigger it? Do you just supply the tube power, and it takes care of firing by itself?

[mixedgas]

Self triggering ignite board, works off tube voltage and cuts off the pulses when the tube goes below 96V or so, tries to ignite when open circuit of 200V or so. That tube likes 8 amps max, 4 amps minimum. Probably a 2.5 VAC cathode.

If that lights, be prepared to leave it run with proper cooling for the first hour or two after ignition to get rid of any hydrogen in the tube, ie let the active gettering activate.

Oh and they sold it to the USA up until the company was bought a few years ago. Probably by somebody with a grudge since 1949... because since say 5 years ago, they refuse to support their former USA market.

I have some schematics back in Akron for that class of laser.

Steve

[jayrob]

You have schematics?

I'm getting one of these exact same laser heads and am hoping to modify this power supply to work with it:
http://cgi.ebay.com/ws/eBayISAPI.dll...=STRK:MEWNX:IT

The enlarged pictures show the voltage and specs...

Any help??

[RedlumX]

EDIT: OK, I have come up with a simple PSU idea.

The first one I built was a similar linear PS with an LM317. I worked fine but generated an enormous amount of heat, I needed a tunnel cooler with forced air for this. On the long term this wasn't very practical.

Note that a 100V cap is not enough, be sure to have at least a 150V or so rating.

[Things]

Yeah, I'm considering bringing the power down to maybe 80-90V so I can use that cap, it seems to be the only option locally. The head says it's operating voltage is 70-100VDC @ 9.1A.

Also, I'm unsure whether the filament runs on AC or DC. On the label on the head, it mentions 3VDC @ 13A ...

[mixedgas]

Yeah, I'm considering bringing the power down to maybe 80-90V so I can use that cap, it seems to be the only option locally. The head says it's operating voltage is 70-100VDC @ 9.1A.

Also, I'm unsure whether the filament runs on AC or DC. On the label on the head, it mentions 3VDC @ 13A ...

-------------

There are a few RARE aircooleds for semiconductor inspection that have DC cathodes and shortened lives. 36 watts is a really small cathode power, I'd check that carefully.

But you need 175-200V open circuit to form the cathode emission spot when the glow transitions to arc and drops to ~90V. Don't sell your self short on starting voltage.

Steve

[mixedgas]

[QUOTE=jayrob;146776]You have schematics?

Why? Doesn't everybody?

yes, I have some schematics for NEC. It may be a week before I can get at them.
I work far away from home, ^%$# lousy economy. Very similar to SP261, those NECs, most of them are pin for pin.

Steve

[Things]

Hi Steve, thanks for the help

I am wondering, what do I need the 200V for? Does the igniter require 200V tube voltage open circuit before it will self trigger or something?

Cheers,
Dan