[turretslug]

Interesting that you also found that- I found much the same with mine when I acquired it quite a long time ago now. HT was around 275V using a US-made metal 5Z4, I expected it to be a little high with typical c.240V mains into a 230V primary winding but not by that much! Once I'd fitted a 220ohm NTC inrush limiter on the primary side (something I like to do if possible on the various valve things around here to give things like switches and dial bulbs a gentler life), losing around 7V, and 2x 82 ohm 2W fusible film (series) between the HT centre-tap fuseholder tag and the reservoir capacitor negative tag, things were nearer the mark. To keep the VR150 operating current down after this, I replaced R7, 27k 1W, with a 12k 1W component now connected to the 150V supply (BFO switch tag) instead of the 235V supply- this diverts approximately 7mA from the VR150 and provides the second mixer, V4 ECH42, with a stabilised screen supply. The designer had provided the first mixer with a stabilised screen supply but not the second, presumably feeling that something connected to an oscillator running at up to 33.6MHz needed it but not the second mixer with its mere 1.535MHz oscillator. I've certainly found when tinkering with various sets that stabilising mixer screen supplies provides an extra dose of frequency stability at higher frequencies. I think it's worth doing something to "tame" the main HT as the N78 in particular is a toasty little valve at the best of times.

Good luck with it, it is a nice set to use when up and running properly.