The old one.
The newer one
Interesting, I know the 5v is 1 amp because it uses a 3 terminal regulator.
I thought the 24V had a higher capacity. The 24V output is simple a 1/2 wave rectifier schema and the diode is rated at 4amps although I do not know what the transformer is rated.
The LV transformer gets its input from the HV circuit using a funky offline switching device [KA5L0380R]. Many times I found that part and other parts on the front end of the LVPS transformer were blown.
In my experience, often the 5V and 24V go out at the same time suggesting the driving circuits fail.
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Iāve seen a few things seem to fail on power-off or power-on lately. Last was a charger for a GEM(street legal āgolf cartā) which was working fine, was unplugged for a quick trip and then when plugged back in DOA. Seems electronics get stressed mostly in those scenarios once aging sets in.
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The new one is bolted to the PCB from the bottom?
You can:
- Mount the old to the case like paul did and wire from the PCB screw holes to the screw terminals on the HVT. That is if there is space to mount the new one. You need the wires routed carefully and connections protected and away from any ground surfaces. The input to that transformer is a nasty >600v.
- You can wait for your new supply.
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It could be that many LPSs have now upgraded their design from the original design so itās not so much an issue. But given the poor cooling airflow design and the hassle of dealing with insulating glues,etc plus how inexpensive the 24V5A PS was it seemed an easy way to remove whatās probably one of the higher heat generating loads from the LPS.
Your eyes have been on this for longer than mine and with a wider audience so your input is greatly valued. thx.
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Iāve kinda of resigned myself to waiting for the new supply now. But thank you so much for your input. 
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Ah, I think adding a 24V supply is a good idea didnāt intend to suggest otherwise.
That is one of the reasons (before there was any rational software like Whisperer) that I got rid of the nano.
In addition:
I always had a problem with the low capacity of the 5V driving the nano.
I do not like anything electrically associated with the HV connected to an expensive controller. Wanted isolation. So the only thing from the controller to the LPS is the L through an optocoupler 
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The race is on. The one that says Tuesday delivery is sold by an Amazon store called Ketofa for $70 and is shipped by Amazon. I have Amazon Prime so Iām hoping it arrives a day earlier as a lot of my orders do. The other one is sold and shipped by OMTech for $55. I only got the Ketofa one because it had the earliest prime delivery date. Will see how they compare.
I am a bit concerned that when I click on the order link for the OMTech one it now shows me this 60W LPS. 
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Ok new LPS here 
(Hold on to your hats because this story has a hell of a twist)
So yea new supply!
Definitely glad I added HV disconnects when I replaced my tube. Made changing out the supply very easy.
So LPS installed, very easy and straight forward. Done.
Turned on the power strip and clicked the on switch. āClickāā¦Nothingā¦):&373)/!shrhdh! What the F-ing hell is going on!
Took some deep breaths to calm my self (inner peaceā¦inner peace) and started working the problem.
Ok, power from the cord 
Check AC pins on the supply, both showing 120Vā
Checked AC on both sides of the switch
Check AC power on both sides of the emergency stop. Cheā¦.wait, one side is open.
Wait for it
OMFG!!! Do you see it?! Do you SEE IT! Arghhh!
There is a bit of the story that I didnāt initially tell because I thought it was irrelevant. Prior to discovering the machine wouldnāt power on initially I had been removing the temp gauge you see on the bottom right of the pic above to try and get the hole size for @Jason_Harrison to install his gauge. Apparently I caused the ring terminal to break off.
Sighā¦
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So why did the troubleshooting guide not find this?
AC power would have been missing from the supply?
Not sure. I had assumed that if I had AC power showing at both of the pins then the LPS was getting power. Is it possible if one side was open it would still show voltage on both pins relative to ground?
Oh Crap, I measured both AC pins relative to ground instead of each other. 
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Wellā¦ back up and running. 
Thank you for everyone who helped out and sorry for being a dumbass.
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Both sides of the line (L & N) is switched with the Estop?
The L leg is hot and would measure 120V relative to both ground and neutral if wiring is correct?
The N leg is connected to the ground in the distribution box so it should read nothing when measured to ground.
So how did you see voltage when measuring both sides of the LPS to the ground? 
Not sure.
Both the L&N go through the Estop
When I measured the L&N at the LPS relative to ground I was seeing 120V on each 
Iāll try and see if I can replicate for you later.
I have a new problem now. Of course. I was trying to characterize the new supply pot V (G-In) vs mA. Got a crazy chart and it plateaus out at 12mA. 
May just say F-it and put the old supply back in. Got it unplugged right now to give it some time to discharge before I touch things.
Putting in the old supply would be worthwhile to see if it still plateaus.
Besides the supply, it could be the tube. Have you been able to run the tube above 12ma prior to the LPS problem?
At above 2.5V is anything arcing or hissing?
Note that this curve is much weaker than the one you plotted new.
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Yeah it could definitely be the tube. Have seen some loss of power. Didnāt notice any arcing or hissing above 2.5V.
Here is old reinstalled LPS vs New.
Crappy supply it looks like.
When old LPS was new (green) vs now (orange)
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Ok, I am so F-ing brain dead right now. Getting ready to pack up the new supply for return and guess what I see?
Unbelievable Canāt believe I didnāt check. Sigh
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Weāve all done stuff like this so donāt be so hard on yourself. We get ātoo closeā to the problem or solution and other aspects creep into the mix. There was one regular 24V poser supply product Iād purchased which had me selecting US/120VAC vs EU/220VAC so naturally I figured it was setup for 120VAC and the PS output voltage was dipping under certain loading conditions. Stuff from China needs us to be a full QC person sometimes.
So now you have a spare LPS for when the āoldā one goes. Now, do you have the energy to redo the plotting? 
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