I have managed to keep the infinite impedance detector, and make it
switchable between it and the plate detector.
The 6sn7 was configured to use 1 section for the bfo and the other
section for the new detector, which plucks the signal from the if
transformer. After that odyssey and replacing some wrong-value
resistors, also found the oscillator fixed pads were monkeyed with,
and the band six pad had a broken solder joint. Looking forward to the
next re-alignment, also with all NOS tubes. Have made a lot of
progress, thanks for your help.
Ben