Adding a Magic Eye - Printable Version

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+--- Thread: Adding a Magic Eye (/showthread.php?tid=2888)

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Adding a Magic Eye - hyounce - 02-02-2011

Does anyone have an idea on how to install a Magic Eye tube in my 41-300? I would like to install a Magic Eye tube in a small project box to set on top of the cabinet, rather than make any changes to the existing radio.

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Re: Adding a Magic Eye - nash - 02-02-2011

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.

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Re: Adding a Magic Eye - hyounce - 02-03-2011

Thanks. I really don't need to do this, but I have fond memories of watching my Grandfather's old, what I believe was a Zenith, and thinking that it was indeed magic. I'll plug it in as an external so it will be completely removable should I eventually get tired of it.

Henry

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