I was hoping to have some good news.
Yesterday sorted out the HT PSU.
Found a polystyrene capacitor in the feedback from the HT in the regulator circuit was intermittantly giving 1.5kOhm resistance, causing the HT to "runaway".
Replaced it, tested the PSU and everything was good, getting -2950V and the grid adjustable to about 300V below this.
Today tested the scope, and nothing on the screen. Flood guns work, but no trace, not even with beam finder.
Testing shows the heater is open circuit in the tube
I did all my testing with the connector off the tube, but one of the initial flashovers must have taken it out.
So the scope is scrap
I will put it into storage and keep an eye out for a tube, but this is the 275MHz version, so not expecting to find one.
Thanks for all the support on the way, I learnt a lot, sometimes just writing about, or expressing issues can be a big help to get ideas together.
On to the next project
