Bill, I don’t have a model 226, but it is possible that someone put in a a switch to go from radio to phono.
I have added a switch on many of the radios I have restored.
I tap into the high end of the volume control and use a switch to choose the input for the volume from either the phono jack or the radio.
It also could have been factory installed, for a record player. Is it a RCA phono switch.
Dan in Calgary