07-01-2018, 03:18 PM
Ed;
If the oscillator isn't working I doubt whether the 6SQ7 has much to do with it, I would focus on the 6SA7 and the circuitry around it on the AM broadcast band, particularly the tank circuit for the oscillator. Quite often there is a 47K ohm resistor in that area that can go up in value causing the oscillator not to work below a certain point, if that has already been replaced then I would look at wiring errors, and finally the B.C oscillator coil and the mica caps. The Mica caps don't often go bad but they sometimes do anyhow.
Regards
Arran
If the oscillator isn't working I doubt whether the 6SQ7 has much to do with it, I would focus on the 6SA7 and the circuitry around it on the AM broadcast band, particularly the tank circuit for the oscillator. Quite often there is a 47K ohm resistor in that area that can go up in value causing the oscillator not to work below a certain point, if that has already been replaced then I would look at wiring errors, and finally the B.C oscillator coil and the mica caps. The Mica caps don't often go bad but they sometimes do anyhow.
Regards
Arran
