[IowaPhilco]

How do I know from a schematic which pins are which on the tube socket sitting in the chassis? The heater pins are easy to identify because of continuity testing and they seem to be larger diameter but what about the others? I can't always trust tracing the circuit because the radio came to me non functioning and the circuitry doesn't appear to be correct in some instances when looking at the schematic. Is there a clock position that's always constant or something? -thanks