Magic Eye tubes have very high impedance and are not harmed by momentary over voltage. Keep input wires short.
Before any accessory is connected to radio on a power outlet make sure transformer is isolating radio set from line power.
Battery on left is AVC (Automatic Volume Control) from radio usually about 0 to - 3.3 volts. The adjustable 1 Megohm resistor is to set tube for fully green eye at peak voltage on strongest station. Bottom left connects to radio ground.
The 12.6 volt lamp between transformers is heater of 1629 Magic Eye Tube.
Use as visual indicator to know when AVC voltage is highest or tuned on the station signal.
