first light: my SP168 actually works!

[Skyko]

History: I obtained this SP168 argon laser and french made 3 phase input switching power supply from a biophysics medical laser about 5 years ago. The laser tube and supply were made in 1988 and the hour meter in the head reads about 525 hours.

So, after 5 years of neglect on a shelf (poor thing), I loaded it up yesterday and took it to GooeyGus's house to try it with his 265 exciter. Long story short, we got hit by a freak snowstorm and abandoned trying to drive north to the 3 phase shop.

Today I decided what the hell, I will cobble together the existing switcher and try and run it from my rotary phase converter (homebuilt job with 7.5hp motor and caps). I spent a good portion of the day reaquainting myself with the biophysics owners manual and learning how to defeat the many interlocks. Hooked everything up, put my meter on the generated leg to see how much it droops, hooked up water (manual says 45psi at 2.5gpm), and got ready for either nothing, sparks, or a loud explosion from a cap or something. None of that happened. What did happen is the filament came on for about 15 seconds, then the laser lit right up first try! Amazing! 5 years on a shelf, maybe a year before that sitting in a warehouse and it fired right up.

It seems to idle at 100mW. You can press +/- buttons on the doctor's control unit to increase power by 30mW increments. I bumped it up to 300mW on the control and it was immediatly burning a hole in electrical tape. I don't have a decent meter, but my coherent lasercheck set at 500nm was reading 410mW when the doctor's control was at 300mW. I then took it up to 800mW and took some pictures. The generated 3 phase leg was reading about 233V at 100mW and 219V at 800mW. I am not really sure how much I want to push the rotary convertor but I am curious how *hot* this laser is. Dang, I still can't get over how these things can work so well after 20 years...

Here are some pics at 800mW:

http://www.photonlexicon.com/forums/...&pictureid=668

http://www.photonlexicon.com/forums/...&pictureid=669

http://www.photonlexicon.com/forums/...&pictureid=670

http://www.photonlexicon.com/forums/...&pictureid=671

[Lasernerd]

Very nice!!
that should go up into the watts

[Laserman532]

that looks like more than one watt to me, and from what I can tell the plasma glow looks like a good color too. Your power supply technology looks a bit sketchey tho

[Lasernerd]

In a normal 3 phase condition 208V do all 3 legs draw the same amount of current?

[Laserman532]

In a normal 3 phase condition 208V do all 3 legs draw the same amount of current?

si senior

[GooeyGus]

Sweet!!! It was great meeting you yesterday, and I'm totally loving this HGM5. I took it up to 22A for about 20 seconds... man... this thing cranks out the power.

Too bad we couldn't light the 168, but that's awesome that you got it running! Hopefully we'll meet up again soon and see if we can really give her some power

[Laserman532]

Sweet!!! It was great meeting you yesterday, and I'm totally loving this HGM5. I took it up to 22A for about 20 seconds... man... this thing cranks out the power.

Too bad we couldn't light the 168, but that's awesome that you got it running! Hopefully we'll meet up again soon and see if we can really give her some power

So hey, you guys had a mini PaNoWeLEM TOO! we have got to stop meeting like this. I was telling platnimum that I am trying to arrange a place here in bend we could light up, may be this spring

[Lasernerd]

So hey, you guys had a mini PaNoWeLEM TOO! we have got to stop meeting like this. I was telling platnimum that I am trying to arrange a place here in bend we could light up, may be this spring

Oh man that would be soooo sweet!
If I can help in any way let me know!

[sugeek]

So hey, you guys had a mini PaNoWeLEM TOO! we have got to stop meeting like this. I was telling platnimum that I am trying to arrange a place here in bend we could light up, may be this spring

Count me in, I am up for a trip around or over the hill! A trip to St. Francis School would be in order too...

-Adam

[Skyko]

So is there a relatively painless way to measure the current going to this SP168 tube so I can determine how healthy it is? Ie, I want to know what it is drawing at say, 500mW output, 1 watt output, etc. I am unsure if my 3 phase converter can take it much above 2 watts or so without the generated leg drooping excessively (but maybe it would be ok since it is a switcher afterall).

Ideally, someone who knows a lot about this biophysics switcher can say, oh, just put a multimeter here and volts reading times x = tube current. (dreaming here).

I have a scanned, reduced size schematic that I can sort of make out represents some sort of power supply but other than that it is mostly too small to read anything. I think there should be some test points in the supply for monitoring current, or maybe there is a shunt in series with the tube I can measure across..