Figure 9.12 Partial schematic showing interconnections of tube filaments.
The lower prong of the line plug goes through the on/off switch to the radio common. The upper prong of the line plug goes to the rectifier anode. The upper prong also goes through a 0.05 u f capacitor to radio common. The rectifier cathode goes to one end of a 150 ohm resistor. The junction of the rectifier and resistor is labeled as having 112 volts on it. (Note: I would take this one with a grain of salt.) The other end of this resistor connects to the positive end of a 40 u f capacitor. This point is labeled 105 volts. The capacitor connection also goes to one end of a 1 k ohm resistor. The other end of the resistor goes to the positive end of a 20 u f capacitor. This point is labeled 55 volts. The negative ends of both capacitors go to radio common. The junction of the 1 k ohm and 20 u f goes to one end of another 1 k ohm resistor. The other end goes to pin 7 of the 3V4. This point is labeled 8.0 volts. The center tap of the filament is pin 5 and it goes through a 220 ohm then a 470 ohm resistor to radio common. The negative end of the filament, pin 1, connects to the junction of the two resistors. Pin 1 of the 3V4 connects to pin 7 of the 1U4, IF amplifier. This point connects through an 80 u f capacitor to radio common. The voltage at this point is 5.3 volts. Pin 1 of the IF amplifier goes to pin 7 of the 1U4 RF amplifier. The voltage at this point is 4.1 volts. Pin 1 of the RF amplifier goes to pin 7 of the detector/first audio, 1U5. Voltage is 2.8 volts. Pin 1 of the 1u5 goes to pin 1 of the 1R5. Voltage is 1.3 volts. Pin 1 of the 1U5 is bypassed to radio common by a 0.05 u f capacitor. Pin 1 of the 1R5 goes to radio common.

End verbal description.
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