Norco Mfg. Co. 4 Super
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|Manufacturer:||Norco Mfg. Co. (Remler)|
This Radio Receiver is of the Superheterodyne type employing the following tubes: # 380 as rectifier; #57 as mixer oscillator #57 as detector and #347 ng audio power amplifier. Tho Mixer-Oscillator tube is located between the #380 tube and the Antenna - R. F. coll. The detector tube is located between the #347 and the oscillator coils.
This set is designed to operate from a standard power supply of 110 to 125 volts. 50 or 60 cycles, alternating current Best results w11 be obtained when operated from a fifty foot antenna and a good ground connected respectively to the red and black wires at the back of the chassis.
The knob at the left controls the volume increasing in a clockwise rotation. This knob also controls the line power switch. The center knob controls the station selector dial. The knob at the right operates the variable tone control.
In the center-front of the Chassis is located the variable tuning condenser. The front section ( nearest the dial) tunes the oscillator plate coil. The back sootia ( nearest the power transformer) tunes the secondary of the R.F. coil.
The antenna - R.F. coil form located at the left of the tuning condenser contains the following windings: At the top in the secondary or grid coil, trimmed by the trimmer condenser mounted on and controlling the back section of the tuning condenser.
At the bottom of the coil form is the resonated antenna coil, capacity coupled to the grid coil by the coupling trimmer on the front of the coil form
The oscillator coil form at the right of the tuning condenser contains the tuned oscillator plate coil which is trimmed by the front section trimmer. The cathode coupling coil is below the tuned section.
Mounted inside of the oscillator coil form is the 250 K.C.l intermediate transformer. The plate or primary section is tuned by the trimmer mounted beneath the chassis and accessible for tuning thru the hole in the chassis between the coil for and the variable condenser. The secondary is tuned by the trimmer at the top of the coil form nearest the detector tube.
The grid bias for the power tube is obtained by a voltage divider system across the choke (dynamic speaker field) on the negative side of the high voltage circuit.
Voltage readings for servicing purposes follow: