Inspired by JH2CLV , I made my decision to convert the old FL2277B with a GU74b.
My goal was to keep it simple. That meant to avoid an enlargement of the original
cabinet. Well, that was a big challenge. But the proof of the pudding is in the eating.
I was happy to had a large libary of circuits for a screen grid supply. PA0FRI was
an excellent source for a low power supply voltage-fed by the filament transformer.
First of all I replaced the old HV capacitors and some of the old doorknobs. Then I
had to build in a transformer for the screen grid supply.