Have you checked audio interstage transformers. They are often open. Even open, some audio may get through.
Since TRF radios have mulitple RF stages connecting an antenna to different tuners will bypass early circuits. An antenna connected to the detector tuner will pick up stations but won't be very selective.
Norm
:I have a '28 TRF Westinghouse, overall reception is weak. Tried tube substitution, voltages seem OK. Capacitors are metal type values unknown. Any suggestions?