[hedora]

I think turning the tuning knob typically popped out the preset button, and holding the button down while turning the tuning knob changed the preset. I think this could be done with a loop of string (to control where the dial arrow was) and few springs and catches (to pull the string into position when the button was pressed).

I can’t imagine how the mechanism would work if each preset knob was a tuning knob.

[myself248]

There was only one knob. To set a preset, you first pull the button out towards you, which released sort of a clamp internal to the mechanism, then push the button back in, and it would clamp on the string at the new position.

I'm gonna have to shoot a video next time I'm at my parents' place, aren't I? (The old Blaupunkt still serves as a stereo in the garage.)

[namibj]

Just have the knob rotation rotate a tuning element, and have the knob pressing switch the tuning element into the receiver circuit.