Need more info on this Hellium Cadmium laser

kristopher said:

Thanks Gooey Gus.  I'll try your suggestions.  The laser head only has 110 hours, so it shouldn't be depleted of Cd (Don't they last ~1000hrs?).
I have checked the HV from the power supply and it looks fine, too.  Since this is the power supply that it was working with before, I don't think that is the issue.
We have a telsa coil that should do the trick, too.
Kristopher

Click to expand...

AND BE PATIENT!

If you get it to light, it may take more than a week (24/7) to get it to lase again. If/when you get it lasing make sure to do the monthly (maybe bi-monthly) maintenance burns.

Peace,
dave

Herein lies the problem.  When the unit is turned on, a plasma discharge is evident.  It isn't lasing (UV checked).  The He heater is disconnected, too.  After about one minute, the plasma stops.  Then, after about five minutes the plasma will ignite, but only for about 30 seconds. After a few attempts, it doesn't try to ignite the plasma anymore.

So, running it for a week might be the solution, but it seems to me the power supply must have some overcurrent limit/time out circuitry.  Anybody have any ideas how to make it run continuously?  The dry ice trick didn't work, and I don't think the tesla coil is needed since there is a plasma discharge.

Thanks a bunch,

Kristopher

This is evident of high helium pressure. There is a trick you can do to 'bypass' the starter delay on a board in the PSU (dont have time to post it now... I will later tonight). You'll need to install a switch or button than you can press right away when the discharge stops to light it again. After doing this a few times it should sustain and keep going. Also, with only 110 hours it should be more than good to go. Usually there is about 5g worth of cadmium, which will last about 5000hours (1mg per hour is the normal consumption rate)

If it is far gone and still won't stay lit, go to your nearest neon sign shop and ask the guy to run the tube for an hour on a "bombarder" transformer set to about 200-400mA depending on how far gone the tube is till the tube is hot enough to scorch paper. That fixes most high pressure liconix He-cd laser tubes, omnichrome tubes require a bit less current because you don't want to melt the internal bore or fry the electron emitting stuff off the filaments (use them both). Make sure the output current is rectified and the cathode is hooked to the - side or your tube will not live through this.

Thanks for the many inputs. I look forward to the details on how to bypass the starter.

I just realized I completely high-jacked this thread - sorry to the original poster.

Any luck finding that Schematic GooeyGus?

K

I know how to do it in my head, but I have to take a picture of a board in the PSU to explain it lol... It's really easy though, it's just tying a pin to ground. I just haven't had a spare second to take this PSU apart to get pics :-[

Chris --

I never thought of a bombarder room for a tube --- Great idea. Just get away from the soft x-rays !!!!!
After sitting for a month and a half, both of my ArIons started on the first spark.

Mike