someone just closed my other thread, but the issue is not solved. I either have a bad PSU or a bad tube and want to report back.
there are 500 hours of output in the 150w tube.
I think that was a consequence of yoinking it into another category. After all, you’d said it was done.
All of which happened while I was typing …
IMO, no, but I don’t have hard proof.
What does kill a power supply, though, is shorting the anode lead to the frame. That can happen with spliced high voltage wiring inside low voltage insulation, but the new supply should have the proper connectors at the end of enough HV wire to get the job done without jank.
The gas inside the tube slowly goes bad on the shelf, even without being used, so it’s not clear keeping a spare tube around is a Good Idea™. Again, I don’t have hard numbers, but the consensus seems a year in the box is too long.
that great intel, thank you.
im seeing 150w tubes for $1200 and some for $2500, not sure which one i need without opening the back. seems like i should try the new PSU I ordered before buying a new tube.
im seeing the machine on ebay for 6 grand, so it better not be the $2500 tube.
The machine was made March 2022. 500 hrs on the tube. Should i just replace the tube also? It’s a critical part of my business, and this is time sensitive. I would rather spend $1200 than lose another 2 weeks with the machine…
Keep in mind I find it remarkably easy to spend your money …
If you have the floor / chiller / vent capacity, ordering a second machine right now, plus buying a tube + power supply for the deader, would make a lot of sense. You get twice the production capacity for surges and keep a hot standby running the rest of the year.
If that’s not feasible, get the tube + power supply and hope for the best …
i have twin 60w machines and those benefits you mentioned are already apparent, so i was already looking at a 2nd 150w machine but i can’t move the shop around in December.
i should have to “hope for the best” with new tube and new PSU? is there a high defect rate?
Did you check the TEM mode of the current tube? Sometimes that identifies the tube as a problem. If it’s not in TEM00 mode, it will never work properly.
The way these work is by increasing the voltage on the tube anode until the tube starts conducting, this is usually referred to as trigger voltage, and indicates minimum voltage to cause the tube to start to lase.
Things to keep in mind about a new lps… I believe these are 100W lps.
If you have questions, ask… 
All I can offer is opinions based on what you’ve reported, not certainties, so we may not have pinned the problem down to the actual cause. If a new power supply or tube doesn’t get the machine working again, I really want to know (while hoping you won’t reach out through the monitor to wring my neck).
As for seller defect rates, reputable suppliers have a pretty good reputation for a reason. A few folks have opened boxes to find shattered tubes, but reputable suppliers quickly put a replacement in the pipeline.
@jkwilborn has a good point: the tube may be shifting in and out of TEM00 mode. If it were a solid failure (always cut poorly), you could check the beam pattern to find out, but that’s hard to do with a tube that intermittently works or doesn’t depending on nothing you can control.
I would not blame you if the tube did not solve, i was more looking for thoughts on how likely a 30 month 500 hour tube was to behave like this.
That spec sheet mentions active cooling fan on the psu which i have heard running before…i will check that tomorrow. If that fan died, throttling after a few minutes could make sense. (I’m not sure how the psu handles over temp)
To make matters worse, i was 100% sure the mirrors were aligned this AM. But they were not dead on when i checked them a few hours later. The first thing i am going to check is the mirror 1 pedastle shifting which is dangerous, but these are separate issues.
I will look into this tem0 mode. I’m confused why this would effect alignment vs mA output, but I’ll take your word for it and check it tomorrow.
So the TEM modes are new to me (thank you) and that may explain the weird burn mark this afternoon on the tape. It’s the first time i had pulsed tape immediatly after a job that was losing power, vs. the typical alignment of the cold machine this morning.
I could see the full circle discoloration on the tape (before it burns), but it was not burning from the center. Part of the outer edge of the circle was very burned, from 9 to 3 on the clock dial. The center and bottom of the circle were not charred. I wish i took a photo.
I had never seen that before…
Just an FYI, when i say the mirrors were spot on, i mean the same spot in all 4 corners of the bed, on tape before mirror 3. But that spot moved after the afternoon… unknown yet if mirror or tube related.
Post a photo of the m1 burn mark and we can comment on it if you wish.
If the tube isn’t resonating correctly, all bets are off on what you see, such as mA or tube anode voltage. When I lost my tube, there were variances in both mA and anode voltage being out of range.
We’ve seen mirror holders work loose: the lock ring holding the mirror into the mount came loose and let the mirror rattle around.
And, although this is downstream of the problems you’re seeing now, a loose focus lens can rattle around inside the laser head.
That definitely seems like a bad tube producing a beam that’s no longer peaked right down the middle. Because it’s no longer collimated the way it should be, the off-axis beam may be heating up the nozzle or something else along the way, rather than coming out the orifice. In any event, the lens can’t focus it properly.
And given that you’ve measured the spot in both modes (good catch!), the differences could explain the flickering I’ve been blaming on a failing power supply.
But, given that power supplies are relatively cheap, I’d definitely replace it along with the spendy tube.
It may have inhaled a mouse, but I’d expect the supply’s protection circuitry to completely cut the power when it overheats. At this point, I’d not lay much money on that assumption, mind you.
Cooling fan was good.
Checked for loose and rattling lens and mirror retaining rings several times. Everything was tight as a tiger.
I’ll have the new tube and psu by the end of the week, and my last xmas orders are shipping tomorrow so I’m going to replace both at the same time asap. While I am curious if the old supply is good, i don’t know enough about if it could hurt the new tube so I’m not going to try it.
Should i keep the old supply, labelled as questionble or trash it?
Thank you for the expertise…btw
On a shelf, just so you can sneer at it, as I do.
IMO, however, you’re enough of a biz that you cannot afford to screw around with probably bad stuff the same way I do. Better to toss it in the e-waste box and move on.
Perhaps I’ve just made a few more mistakes and learned from other folks making theirs… 