[RadioDR401]

Thanks for the tips!  I also hit upon another idea to test the stage gain.  I metered the AVC line with the antenna wire on the clip, then on the 44 grid and finally on the 77 grid.  The RF stage is definitely working since I got about -2.3 volts from a weak station with the antenna on the clip vs about -0.8 on the 77 grid.  The station sounds about the same but clearly the RF stage is working.  I'll try the IF stages next as you suggested.