Trouble firing up my new HeNe tube

[LtKernelPanic]

I picked up this little 6" HeNe tube off flebay last weekend and am having problems getting it fired up. I tried both my red HeNe PSUs but I haven't even got a flicker from it. If I did things correctly the cathode is can end of the tube and the anode being the clear end. The only ting I can think of is the mounts that came with my HeNe kit isn't making proper contact. Do I need to make contact with the round metal part right next to the tube instead?

Here's a pic of the tube.


2012-04-04_09-07-38pm by ltkernelpanic, on Flickr

 

[n2stuff]

Can you take a pic of it hooked up with psu. Like this...

 

[daguin]

I picked up this little 6" HeNe tube off flebay last weekend and am having problems getting it fired up. I tried both my red HeNe PSUs but I haven't even got a flicker from it. If I did things correctly the cathode is can end of the tube and the anode being the clear end. The only ting I can think of is the mounts that came with my HeNe kit isn't making proper contact. Do I need to make contact with the round metal part right next to the tube instead?

Here's a pic of the tube.


2012-04-04_09-07-38pm by ltkernelpanic, on Flickr

At the voltages that these run, you don't need a "good" connection for it to work

When I test them I simply lay the bare end of a wire over the end of the tube

Peace,
dave

 

[Hemlock_Mike]

Like Dave says -- at these voltages, you should have a plasma
IF the PS is working. Are you sure you have HIGH voltage?
Be careful :-(
HMike

 

[LtKernelPanic]

Yeah the PSUs are putting out HV fine. One of the them and the tube mounts I was using is from one of Sam's HeNe kits (Helium-Neon Laser Kit 1) It fired that tube right up when I swapped it back in. The other PSU is the one that came with another tube I bought awhile ago. It too works fine. There are no obvious signs the tube is damaged and out gassed so I'm suspecting something isn't making contact.

edit: I do have one of the same PSUs that n2stuff has in his pic on the way. It should be here Friday. Maybe it'll do the trick.

edit #2: I dug out an extra alden style HeNe power cable I have and hooked it directly to the tub and still got nothing. I did look at the tube a bit closer and there's a chip in the edge of the HR mirror probably from when the tube was removed from whatever it was in. The part of the mirror that meets the tube is fine so that shouldn't have any effect on it. As much as I hate to admit it it looks like this tube may be toast. =/

 

[Cyparagon]

Put it near a high frequency high voltage source like a plasma ball to check for gas. You could also put it in the microwave for a few seconds.

 

[LtKernelPanic]

I don't have a plasma ball so I popped it in the micro for 5 seconds. No glow at all. Looks like this tube contains only air. Looks like my hunt for an small red HeNe tube that shows a lot of plasma continues.

 

[JLSE]

I don't have a plasma ball so I popped it in the micro for 5 seconds. No glow at all. Looks like this tube contains only air. Looks like my hunt for an small red HeNe tube that shows a lot of plasma continues.

I have 1 or 2 of these tiny tubes.. No P/S though.. PM with
an offer if interested.

:beer:

 

[daguin]

If you're going to stay working with used gas lasers, you should really get (or build) yourself an oudin coil

Peace,
dave

 

[Solonar]

Looking at the serial #, that looks like one of the 05-LHR-006's that I made in 1988.

The cathode seal and the gas fill tube are the normal failure points. If the Glass to kovar seal looks silvery the tube may have leaked. If the fill tube has been damaged at the crimp, its possible it leaked also.

if its the smaller 05-LHR-007, they were notorious for cracking on the cathode seal during manufacturing. We typically had <50% yield.

 

[Sigurthr]

If you're going to stay working with used gas lasers, you should really get (or build) yourself an oudin coil

Peace,
dave

Finding one marked as Oudin is tough these days though, they are most often mistakenly called Tesla coils. You can sometimes find old vintage ones on eBay labeled as "Violet Ray", they're an old quack medicine device.

Speaking of Quack... you could also hire le Quack to build you a HV flyback unit, which would work for the same purpose.

 

[daguin]

Oudin Coil w/Safety Switch

Peace,
dave

 

[LtKernelPanic]

If you're going to stay working with used gas lasers, you should really get (or build) yourself an oudin coil

Peace,
dave

Heh I was wishing I had one last night. I may have to look into building one but I've never built anything like that before so I'm going to have to do some research on them. It only cost me 20 bucks so I'm not out much. I'll feel bad if the others who bough them get air tubes as well.

 

[Sigurthr]

Aye, thanks for that link, Dave! I had it saved a long time ago but couldn't find it when I was looking for it a few months back.

Back to checking HeNe's...
~$200 for one of those, or $60 for a Le Quack HV board.

 

[daguin]

Heh I was wishing I had one last night. I may have to look into building one but I've never built anything like that before so I'm going to have to do some research on them. It only cost me 20 bucks so I'm not out much. I'll feel bad if the others who bough them get air tubes as well.

If you have the patience, it definitely looks like it would be a fairly easy build

Peace,
dave

Here's a cheaper one
Ewards Tesla Coil Hand Held Probe Detector | eBay

 

[Solonar]

We used to keep one of those coils next to each of the vacuum processing systems for the HeNe's.