Emanuele, as you seek out more and more long-shot ideas for your original problem set, sometime you might contemplate the probability that an “almost same” C7 ?somehow managed to get the right S-85 part number put on it [ but only the min capacitance was not as low] and then ?put in your radio, and perhaps it got passed along as a shelf queen all this time, passing from one SWL to another.

Without having Jim undo his wires maybe you two can visually measure/compare the rotor to stator gaps when wide open or something?