Hi Rodger;
It sounds like you may need to walk your mirrors in. That 909 tube should be making a hell of a lot more than 130 mw! More like 1-2 watts! The spot on the wall should be damn near blinding to look at when you have the PSU turned up.
My smaller, air-cooled 903 tube is cranking out something north of a watt right now. (Don't have a power meter that goes up high enough to say just how far north of a watt it's actually running.) And this was after a *very* brief adjustment of the mirrors. My guess is that your optical cavity is similarly misaligned.
Put it this way - my tube is smaller than yours, yet it will melt black plastic. So your 909 tube should be downright dangerous when it's lasing properly. Give the mirrors a tweak and see where you end up. (Only move one adjustment at a time, and go back and fourth 1/3 of a turn or so until you get it peaked. If you don't see a change, then put it back where it was and try the next corner.)
The purpose of these wires is to pull in the relay that controls the blower. Since you don't have the original back panel for your power supply, you don't have this blower or the relay that energizes it. You can simply insulate the wires, or you could use them to power another relay if you wanted to add additional cooling to your head. (That's what I'm going to do with mine anyway.) The relay will pull in as soon as you power up, and will stay on even if you break the interlock.Label B – two wires – purpose remains unknown. They can be insulated and left unconnected to anything.
I have confirmed that this connector *is* in fact designed for you to be able to measure tube current. It's isolated from the starting pulse too, so you don't need to worry about frying your meter. Unfortunately, I don't know what the conversion factor is from volts to tube current. (Still researching that.) I get readings ranging from .46 volts at idle to 1.36 volts with the tube maxed out.Label D – two wires – Adam suggested these might be the tube current monitor but I have not tested them yet. In any case they do not need to be connected to anything.
Hmmm... I believe this is already grounded on my unit, but I'll need to check that. (Maybe it's grounded through one of the other circuits on the extra control boards I have on the front of my unit.)There is a solid state relay (SSR) mounted on the big black heatsink that says “Danger High Voltage” in the picture. The SSR is on the side opposite the cooling fans and on the far left as seen in this picture. It has inputs labeled + and -. Connect the negative input of the solid state relay to ground (I used the chassis on the back of the PSU as seen in the picture – NOT the heatsink.)
Which control board? I don't see one in your picture. On my unit I have three boards in front of the main PSU module that you show in your picture. Which of the three do you still have on yours? (Which one has this resistor on it?) Can you take a picture of it?The variable resistor R13 on the control board is said to regulate the tube current but I have not played with that yet.
I'm adjusting my tube current by using the aiming beam intensity knob on the face of the PSU. (You don't have this.) Also, if I select "continuous treatment" and step on the pedal, I can use the intensity control on the face to dial up the current. But since the aiming control does the same thing without having to hold the pedal down, I've been doing that instead.
That doesn't sound good. I don't have any flicker at all. It could be oscillation in the plasma I suppose. Or it could be that you're right on the verge of loosing the beam because the mirrors are out of alignment, and slight thermal changes are enough to throw it out. When it flickers, does the plasma glow remain constant, or does the whole tube flicker? (Not just the beam, but the plasma glow as well.?.) If the plasma itself is going out, that's bad.After my laser has been running for a minute or two the intensity starts to flicker mildly. The flicker seems to come and go randomly. My arrangement does not have optical feedback (yet) although the power supply does have this capability built into the control board. Maybe optical feedback would resolve the flicker???
Adam