[Radioroslyn]

Methinks your issue is in the audio amp rather than the rf/if stages so far. With C-15 disconnected from the vc and you touching it w/ your magnetic personality it should buzz loudly. Is the voice coil stuck to the pole (spkr cone not moving freely) ? If you measure the resistance from the 35L6 p5 to B-  and p2 of the 12SQ7 to B- both should show a high resistance (abt .5M and 5M respectively). Typically the output transformer would cause low audio w/o have other signs ( low plate voltage on the op tube). Does your signal generator have a 400cy audio output?? If so try feeding the 400cy tone into pin 5 of the 35L6 to hear how much volume you can get.