03-24-2015, 09:24 AM
I have checked both the antenna coil and the RF transformer which both precede the oscillator. They seem to have correct continuity at all points.
With the 4 feet of wire attached to the 36 tube, pin 4, and the oscillator oscillating, I disconnect the wire from the antenna terminal. Performance drops, of course, but the oscillator keeps oscillating. I can tell through the zero beat I hear in the transistor radio I hold up to the Philco. However, in all cases, when I disconnect the wire from pin 4 of the 36 tube, the oscillator cuts out. I no longer hear the zero beat in the transistor radio.
It seems like that wire connected to pin 4 is adding something. I don't know if it is acting like a "gimmick capacitor" or something like that?
I will keep experimenting. I know from much reading that the 36 oscillator circuit in the Philco Model 19/89 can be very finicky.
Thanks,
Mark
With the 4 feet of wire attached to the 36 tube, pin 4, and the oscillator oscillating, I disconnect the wire from the antenna terminal. Performance drops, of course, but the oscillator keeps oscillating. I can tell through the zero beat I hear in the transistor radio I hold up to the Philco. However, in all cases, when I disconnect the wire from pin 4 of the 36 tube, the oscillator cuts out. I no longer hear the zero beat in the transistor radio.
It seems like that wire connected to pin 4 is adding something. I don't know if it is acting like a "gimmick capacitor" or something like that?
I will keep experimenting. I know from much reading that the 36 oscillator circuit in the Philco Model 19/89 can be very finicky.
Thanks,
Mark