I have a Heathkit SB-610 monitor scope that I refurbished a few months
back. I connected it to my SB-301 receiver by tapping the secondary of
its last intermediate frequency (IF) transformer (T4 in the 301's
schematic) using a 1pf capacitor and RG62 cable as recommended in the
610's manual. After adjusting (“peaking”) the receiver IF transformer
and the coils in SB-610, the scope worked, but the trace didn’t have
much vertical deflection, even with the 610’s vertical gain control
fully rotated clockwise.

My remedy for the small trace was to build a tuned pre-amplifier using
a 2N3904 transistor. The extra 20dB of gain it provides produces a
trace that’s about 1 inch high for an S9 signal and the vertical gain
control at 12 o’clock. All is well.

So here’s my question: Building the pre-amp was a fun and useful
project, but is my scope’s performance without the pre-amp typical?

-Dave Drumheller, K3WQ