Trying to hit the sack, but I keep forgetting to ask you
Have you’ve ever seen one with the cathode disconnected?
That would happen if the ma meter opened up.
Wouldn’t that ‘emulate’ a bad tube also? Back to the unloaded lps?
Understand about the fine wire.
Built a Tesla coil in the 5th grade with a ‘used’ commercial AM transmitter tube for the oscillator. Had to build the 800 volt plate power supply for it.
My dad helped me wind the secondary coil by making a jig for it to rotate. It was almost 3’ long, lots of winding.
I have a plugged connection wire to the PWM output, just for the scope trigger… 
Thanks for your time… Take care
