01-31-2013, 08:03 PM
I'm wondering if the oscillator is running. Make some basic voltage checks on the 12AU6 convertor tube. The grid (pin 1) should read about -3 volts or more if the oscillator is running, otherwise it will read zero.
Another method is to use a working radio tuned to around 1455 nearby. Tune the radio in question to 1000 and should hear zero beat in the working radio. Oscillators are designed to run 455 Khz above the incoming antenna signal.
If the oscillator is running then the loop antenna taken from a Philco as an ad hock replacement may have an inductance to far out of tolerance to resonate with the gang/trimmer capacitance. Hate to think an LCR meter is called for.
It's also good practice to make basic voltage checks on all tubes after a restoration.
Another method is to use a working radio tuned to around 1455 nearby. Tune the radio in question to 1000 and should hear zero beat in the working radio. Oscillators are designed to run 455 Khz above the incoming antenna signal.
If the oscillator is running then the loop antenna taken from a Philco as an ad hock replacement may have an inductance to far out of tolerance to resonate with the gang/trimmer capacitance. Hate to think an LCR meter is called for.
It's also good practice to make basic voltage checks on all tubes after a restoration.
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