02-02-2011, 07:46 PM
In general, you would need to bring 6.3 VAC filament, plate voltage, and AVC voltage to the Magic Eye tube. You can pick off the AVC (Automatic Volume Control) voltage from the 2.2 meg ohm resistor connected to the 7C6 diodes. The 2.2 meg resistor feeds AVC voltage to the grid of the 7B7 first IF tube (via the secondary winding of the first IF transformer)
Exact biasing of the Eye tube would require a little experimentation with how it reacts to the AVC voltage levels. I'm sure a peek at schematics of sets using an Eye tube will give a good starting point. Take a look at http://home.pacbell.net/philbert/tuning_eye/avc&eye.htm for a discussion on biasing Eye tubes.
Exact biasing of the Eye tube would require a little experimentation with how it reacts to the AVC voltage levels. I'm sure a peek at schematics of sets using an Eye tube will give a good starting point. Take a look at http://home.pacbell.net/philbert/tuning_eye/avc&eye.htm for a discussion on biasing Eye tubes.
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