Sorry Ralph, there is nothing behind the knobs to adjust anything [that I can see.].
The knobs are [ on/off, volume] [ tone] [band switch] and [ radio/phono.]
If you look at the photos you can see that the only knobs that are there are those four, and none of them are push/pull.
The radio is in the garage , but tomorrow I will bring it in and take some more photos.
I appreciate you looking into it , and it has me baffled,so far.
Dan in Calgary
