[Patrick]

Yes, but when manual tuning is selected, the whole variable capacitor and associated coils and contact to them are suspect. If there is a short or open in the associated variable capacitor or coils, or fault in the switch, it will not work.  Of course, it's usually the other way around, push buttons not working, variable OK, but this is what you appear to have.

That was my first thought. However, all 4 windings of the oscillator coil are fine. I removed it from the circuit before checking since the resistance of each winding is so small. Did the same thing to the switch. All 12 postions are making contact at the proper time. The insulator on the trimmer for 20B is intact. But since the variable cap consists only of metal plates, and I can get one station which I lose when I move the cap, how could it be suspect? What's left in the circuit?