Argon problem

[Things]

Well, the other night I got my little NEC argon fired up for the first time in many years, from a JDSU 2111 power supply. For the first night, as well as a few hours the next day, it was fine, however during that day, I turned the argon off so I could move it to a different bench. Well, after that, it really didnt want to start again. I connected up a faster ignitor board, and it managed to start it, however the power seems to have dropped off dramatically, and I've lost all the lines I had

I must note, I did leave it trying to ignite for quite a long time, as it really did not want to start, so maybe I have sputtered the cathode coatings everywhere? Anyway ..

Here are the lines when it was working nicely:



And now, these are the only 2 lines that lase, and the red circled one drops off shortly after starting the tube up:



There are a few things I have noticed, that I'm not quite sure on, that I hope some of the more knowledgeable here could clear up for me?

- There seems to be a fair bit of pink coming out the back mirror?
- Filament seems a bit brighter then when I first powered it up? Maybe shorted turns?
- Beam is slightly unstable, as if the plasma channel is wobbling
- The PSU makes a kind of high voltage fluctuating/hissing sound if I try crank the current up, and the argon goes out if you let it do that/go past that
- Power and lines dropping
- The full current NOW seems only about as bright as idle when it was working properly, and idle NOW, it doesn't even lase

The tube does have 9200+ hours on it, and has been sitting for a few years unpowered. It's a GLG3078.

Cheers,
Dan

[Things]

OK, I think I've just made a breakthrough!

While it was running full current, I grabbed a peice of plastic tube and lightly tapped the back mirror mount, and saw a flash from a green line. So I pushed down on it a bit harder and lines started reappearing!!

Only problem is, there is no obvious way of adjusting the mirror mount, and it;s clearly going out of whack during thermal expansion. Anyone know how I could make some adjustments? Maybe some nylon string and a few screws to pull it down lightly?



EDIT: Success! Now back to lasing ALL lines I had before



I still need to figure out a more solid way of adjustment though, if anyone has any ideas

Cheers,
Dan