What is wrong with this 150W?

[Dave Sheldrake]

Check out the Sarbarmultimedia YouTube channel. This guy is amazing. I can't find the particular video but he shows how the power output is not linear like the percentage numbers would suggest. The rise is very steep from 0 to 20 or 30% or so, then flattens out to a much lower slope from that point. That would explain the results you got in pic 3, 500 speed.

Except power IS linear, the problem is that PSU's get set to over current by the manufacturer to make the machine seem more powerful than the tube really is, so what may be say 25mA for a safe limit on an 80 watt RECI may not be what it's getting at 100% or 30% I hear this comments about Russ's videos almost every day and the theory is flawed.

You MUST find out what current the power supply is giving out, until you know that you will be chasing your tail ...30%...50%...200%,2000%.....PERCENT of WHAT!

It CANNOT be checked by the manufacturer using teamviewer as it's a physical check that has to be done (the adjustment is made on a Potentometer inside the psu)

even a cheap junker Chinese supply can put out 50mA if the current limiter isn't set up properly when it's made, on a 40 watt tube that is supposed to run at 14mA even at 35% of 50mA you will be killing your tube.

The power distribution curve on a DC pumped tube is linear until you reach photon saturation or a state where there is no longer any gas at base state that can be excited by the plasma., at that point you will start to get a lot less for more input until the tube reaches it's failure point.