Thanks Tony. I've never come across a KY80 before- I'll have to look it up! I don't have many spare valves with me on the Island, so a PL504 was all I could find which has a similar heater voltage and current. It seemed to work fine lashed in with terminal block
. It was only to prove a point, which it did. I couldn't find anything to replace the U26- only a DY86 and an EY87 which have different heater requirements.
I imagine the portable also acted as a very efficient room heater!!
Cheers
Nick