FRG-7 CIRCUIT DIAGRAM

Component Identification and Connections

This document presents the circuit diagram for the FRG-7 communications receiver, detailing its electronic components and their interconnections.

Input and Control Switches

The diagram begins with input connectors J1, J2, J3, and a MUTE function. Switch SW1 is associated with J1. Switch S1 offers ATT, LOCAL, OFF, and OX settings. Switches S2a through S2f are used for various circuit selections.

Components in this area include capacitors C4 (22pF), resistors R2 (10kΩ), R3 (100Ω), R4 (1kΩ), and reference labels PB-1525 and PB-1560.

Main RF/IF Stages

This section details the core radio frequency (RF) and intermediate frequency (IF) stages, comprising multiple transistors and integrated circuits.

Transistors: Q101 (3SK40M), Q102, Q103 (2SK19GR x2), Q104 (3SK40M), Q105 (2SK19GR), Q107, Q108, Q109 (2SC784(0)), Q110, Q111 (2SC372YX2).

Integrated Circuit: Q106 (SN76514N).

Variable Capacitor: VC1 (36pF x 2).

IF Filter: FL-1 (455kHz).

Transformers: T101 through T116, TC101 through TC104.

Inductors: L101 through L104.

Capacitors: A comprehensive list including C101 (20pF) to C159 (1pF), with values such as 0.01µF, 33pF, 47pF, 0.047µF, 22pF, 100pF, 2P, 5P, 6.8P, 1P, 47P, 2P, 5P.

Resistors: A wide range from R101 (100kΩ) to R156 (100Ω), including values like 220Ω, 10kΩ, 470Ω, 27kΩ, 1kΩ, 3.3kΩ, 82kΩ, 47kΩ, 6.8kΩ, 18kΩ, 120Ω, 15kΩ, 470Ω, 100Ω.

Diodes: DX02 (IS1555), D101 (SL103).

Test Points: TP101 through TP107 are marked for measurement.

Labels: AOC (Automatic Output Control), IOV (Intermediate Output Voltage), MAX 320P (Maximum 320 PicoFarads).

Oscillator Units

The circuit incorporates dedicated oscillator units.

OSC UNIT PB-1523: Features transistor Q201 (2SC784(0)) and a dual variable capacitor VC201 (36pF x 2). It is connected to transformers TC201, TC202, TC203, TC204, and capacitors C201 (22kΩ), C202 (0.01µF), C203 (22pF), C204 (33pF), C205 (1kΩ), C206 (1kΩ), and resistors R201 (22kΩ), R202 (4.7kΩ), R203 (1kΩ), R204 (100Ω), R205 (100Ω).

HG UNIT PB-1524: Includes transistor Q301 (2SC372Y), inductors L301 (0.01µH), L302 (0.01µH), L303 (series L303-1 to L303-4), L304 (3.9mH), capacitors C301 through C311 (values include 0.01µF, 27pF, 8pF, 5pF), and resistors R301 through R306 (values include 100kΩ, 220Ω).

Test Points: TP301, TP302 are indicated.

Audio and Output Stages

This section covers the audio amplification and output circuitry.

Transistors: Q401 (3SK40M), Q402 (2SK19GR), Q403 (2SC372Y), Q404 (2SK19GR), Q405 (2SC372Y), Q406 (2SC372Y), Q407 (2SC372Y), Q408 (2SK19GR), Q409 (2SC372Y), Q411 (2SD313).

Integrated Circuit: Q410 (AN-214).

Transformers: T401 through T406.

Inductors: L401 (4.7nH), L402 (3.9mH), L403 (3.9mH), L404 (39mH), L405 (68nH), L406 (3.9mH).

Capacitors: A broad range from C401 to C457, with values such as 0.01µF, 0.047µF, 22pF, 1P, 47µF, 2.2µF, 100pF, 10P, 0.2µF, 100µF, 3.3µF, 33µF, 0.003µF, 1000µF (25WV).

Resistors: From R401 (100kΩ) to R457 (100Ω), including values like 100kΩ, 47kΩ, 220kΩ, 100Ω, 33kΩ, 18kΩ, 1kΩ, 2.2kΩ, 3.3kΩ, 150Ω, 100µF, 68kΩ, 220Ω, 100Ω, 18kΩ, 120Ω, 22kΩ, 15kΩ, 470Ω, 33kΩ, 2.2kΩ.

Variable Resistor: VR401 (500kΩ B).

Test Points: TP401 through TP408 are indicated.

Power Supply and Output Jacks

This section details the power input, control, and audio output connections.

Power Input: Connections for BATT (Battery) and EXT BATT (External Battery) via connectors J6 and J5. A transformer PT is shown with primary windings labeled 120, 100, 120, 100 and secondary outputs labeled 10.5V, 10.5V. A 9V supply is indicated near TP302.

Controls: Switch S5-b is present. Switch S6 controls the LIGHT function (OFF/ON). A TONE S4 control offers NARROW-NOR-LOW settings, utilizing components like PB-1525(1/2), variable resistor VR1 (10kΩ A), resistors R7 (3.3kΩ), R8 (3.3kΩ), and R10 (77kΩ), along with capacitors C1 (0.02µF) and C2 (0.02µF).

Output Jacks: J4 for PHONES, J7 for EXT-SP (External Speaker), and J3 for RECORD.

Speaker Symbol: SP indicates a speaker connection.

Notes

The following general notes apply to the circuit diagram:

ALL RESISTORS ARE IN 1/4W UNLESS OTHERWISE NOTED.
ALL CAPACITORS ARE IN µF UNLESS OTHERWISE NOTED.
ALL ELECTROLYTIC CAPACITORS ARE 16WV UNLESS OTHERWISE NOTED.

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