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.