HeNe sputters then dies.

I've got a HeNe and everytime I touch the tube the output flickers, then shuts off. This only happens when I touch it. If I turn on the PSU (and if the HeNe successfully ignites) and leave it alone nothing happens, the output is stable. As soon as I touch the tube case it goes haywire.
This HeNe is dear to me and I would like to fix the problem if possible.

Does anyone know what causes this?

It's a melles griot 05-LHP-153 with a 1.7kV 1201-1 Uniphase PSU.

Touching it increases the capacitance of the tube. Try adding more ballast resistance and if that doesn't help try turning up the current.

Change the Ballast resistance value up and down by ~1K at
a time to where the Laser stays lit with the PS you have.
Or as Sigurthr stated... if your PS has an adjustable output
change the current settings to get it to stay lit.

It may also be your PS getting weal and not outputting enough
current.


Jerry