So I've been working on a Stewart Warner 9100B with a Raytheon chassis, got it working pretty well after spending a few days trying to get the heater string sorted out, recapped almost completely, working fairly well with just a little sync problem when suddenly it dies on me!
Picture just faded out and a faint sizzling noise like a cap that was venting. Nothing as easy as that though, more like the HV transformer took a dump!

Note, this set is a 10" set but it uses a oscillator HV supply just like the 7" electrostatics do but bigger. No doubt a complete unobtainium part.