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Thread: Reviving Liconix 4050 HeCd

  1. #1
    Join Date
    Jan 2013
    Location
    Santa Rosa, CA
    Posts
    133

    Default Reviving Liconix 4050 HeCd

    I dug out my Liconix 4050 HeCd from under the bed, this weekend. She's been there for 6+ years, I'm sorry to say and she doesn't fire up any longer. My notes suggest she measured at 3mW in 2011.

    What she does now is arc. I can hear the 4050PS trying to get her started by the regular arcing sound I hear about one per second. I tried letting her warm-up for a good 20 minutes before giving up. I'm concerned about the power supply by letting it arc for too long a duration.

    Unpowered, I did some tests using a high-frequency RF generator and I'm not seeing much activity inside the tube. I'm concerned she's too empty of gas to lase any longer. If this is just a heater failure, would I not still see activity within the tube using the HRF generator?

    Has anyone refilled these tubes? Can it even be done? Who does it and how much does it cost?

    I'm a hobbyist with a small collection of HeNe, Argon and Kryton tubes. But this one may be too far gone to resurrect.

    I invite any advice to get her working.

  2. #2
    Join Date
    Jul 2009
    Location
    Orlando, FL
    Posts
    363

    Default

    Sounds like itís gone high pressure- those older liconix HeCd lasers have soft sealed brewster windows. Hit it with the oudin coil again and if you see a golden/yellow color, that is most likely nitrogen contamination from air.

    These can be revived on occasion. I once got a high-pressure tube to start by packing it with dry ice and letting it chill until the tube pressure dropped enough.

    These tubes can be reprocessed and itís not too hard (if you have substantial experience with High vacuum systems and glasswork), but the kicker is going to be finding someone who is willing to expose their very clean vacuum system to potential cadmium contamination.

  3. #3
    Join Date
    Jan 2013
    Location
    Santa Rosa, CA
    Posts
    133

    Default

    Thanks for the reply.

    I don't recall ever putting the Oudin coil to this or any other HeCd tube in the past. But when I do presently, I see don't see anything plasma inside. Nothing. No color whatsoever. I'm thinking I should see something, and I'm left feeling it's now atmosphere.

  4. #4
    Join Date
    Nov 2008
    Location
    Cleveland Ohio
    Posts
    2,508

    Default

    Dale@hhr-Lasers.com. He is about the last doing these. You canít get he3 at a reasonable price if at all to do it. Itís like 2500/liter.

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