snip

You have a strange problem!

When I pulled the base off of my 545 scope's crt, the HV supply didn't like
it at all. With no load, it started snapping and sparking from the
multplyer chain to the HV supply's case!

That would make sense if there was no "good" return path for the hv.
Interesting. I think I may just move on to bigger and better things,
the scope's working for now, and I have a spare with some really
serious issues (I was debating trying to get two working, now I really
don't think it's worth it)

Steve