[Hallicrafters] SP44/S40A advice please

[Julian Bunn]

I'd like some advice on connecting an SP44 to an S40A. Both devices work 
well independently,
and are carefully aligned. But when I attach the SP44 coax lead between 
Pin 3 (the plate) of
the S40A's V2 (6SA7) and ground, it kills the performance of the S40A 
almost completely ... although
I can still tune some very strong signals, and pips appear on the SP44 
and move as I tune the
S40A.

V2 is the Mixer tube ... which I assume is the same as the "Converter" 
tube referred to in the
SP44 instruction manual.

Or am I completely up a gum tree?! What am I doing wrong?

Many thanks,
Julian