Cool set
No such thing as a stupid question
- stupid is not asking
Sometimes they used the speaker field coil as a filter choke in the power supply. Makes sense really - why not make it do double duty?
Also means if you replace a field coil speaker in a radio or TV with a PM (permanent magnet) one, you'll need to splice in a choke or resistor to take it's place.
And like Charlie said - change those caps! Unlike tubes, they don't ago so well.