[Keith]

Thanks all,

Sounds like I was lucky not to damage probe or scope input. Either that or the pulse voltage is not as high as it should be. There's an old AVO high voltage probe in an auction that I'm attending next weekend - at least it might be a way of determining my EHT voltage. I'll also check the brightness pot, although the effect seems quite gradual as I turn it up. The metrosil has been replaced with a 1N4007 at some point. I added a potential divider as the diode was giving about 700V on A1. What values are recommended for this, I wonder? Also the beam current would be easy to test as suggested by Hugo. Looking at the gun end in the dark I can't see any ionisation glow so hopefully the vacuum is still reasonable.