CO2 Laser failure?

Thanks for looking at my post.

I have little experience with CO2 lasers and am having problems with laser output on 60w RedSail X700. I think that my laser tube may be bad. When it fires, I only have plasma at the Anode and the Cathode. The space between the Anode and the Cathode appears clear (if i turn off the light, I have a very-very small amount of plasma showing).

If I do a full power Amp test by going from the tube Cathode to the laser PSU ground return line, I read 3.2ma. Shouldn't I be getting more like 28ma? Testing the TTL logic line to the PSU shows 4.6v at full power (standby is measured at 4.7) and 2.5v at half power. So it would seem that the control board is sending the correct signal to the PSU. I had a new spare 60 watt PSU, so I swapped out the old one and had exactly the same results. I have ordered a 20K ohm wire-wound resistor and will check PSU output once it arrives, but my current thinking is that the tube is bad.

My question is, since I have little experience with CO2 lasers, should there be a "robust" plasma in the space between the Anode and the Cathode? I have watched test firing of CO2 lasers on Youtube, and it seems like there is a very visible plasma even in room light. My laser tube looks nothing like the ones I've seen on line. In fact, it never looked like the ones I have watched online. I feel like that I am doing all this testing, and probably all I need to do is look at the plasma! Your comments on laser plasma in a known good tube would be greatly appreciated.

Thanks for your time.