Kenwood R-600 Service Manual

The Kenwood R-600 is a professional communications receiver featuring AM/FM/SSB reception, digital frequency synthesis, quartz crystal filtering, and comprehensive tuning capabilities. This service manual covers technical specifications, circuit descriptions, alignment procedures, troubleshooting, and maintenance guidelines for qualified service technicians.

Technical Specifications

Complete technical specifications and performance characteristics of the Kenwood R-600 receiver.

Block Diagram Overview

Functional block diagram showing signal flow and major circuit sections.

1. RF Amplifier Stage: Front-end amplification and preselection
2. First Mixer: Converts RF to 8.83 MHz first IF
3. First IF Amplifier: 8.83 MHz crystal filter stage
4. Second Mixer: Converts to 455 kHz second IF
5. Second IF Amplifier: Main selectivity and AGC
6. Detector Circuits: AM, SSB, and FM detection
7. Audio Amplifier: Audio processing and output
8. PLL Synthesizer: Frequency generation and control

WARNING! High voltages present in power supply section. Exercise extreme caution.

Circuit Descriptions

Detailed description of major circuit functions and operation.

1. RF Circuit: Broadband RF amplifier with input protection
2. First Mixer: Double-balanced mixer using FET devices
3. PLL Synthesizer: Digital frequency synthesis with TC5081 IC
4. IF Stages: Cascaded amplifier stages with ceramic filters
5. AGC System: Fast-attack, slow-decay AGC for all modes
6. Audio System: Low-distortion audio amplifier with tone control
7. Power Supply: Linear regulated supply with overcurrent protection

CAUTION! Static-sensitive components present. Use proper grounding.

Alignment Procedures

• Required Equipment: Signal generator, oscilloscope, frequency counter, VOM
• PLL Alignment: Adjust VCO for proper lock range
• IF Alignment: Peak IF transformers for maximum gain
• RF Alignment: Adjust preselector for flat response
• Audio Alignment: Set distortion levels and frequency response
• AGC Alignment: Adjust AGC timing and threshold
• S-Meter Calibration: Calibrate S-meter for accurate readings
• Final Testing: Verify all specifications meet factory standards

Disassembly Instructions

Step-by-step disassembly procedure for service access.

Front Panel Removal: POWER, FUNCTION switches, tuning knob assembly.

Main Assembly: Remove bottom cover screws, lift chassis from cabinet.

Circuit Boards: RF board, IF board, control board, power supply board.

Voltage Measurements

Critical voltage test points and expected values.

1. Turn off receiver and disconnect from AC power before measurements.
2. Identify test points on schematic and physical layout.
3. Use high-impedance digital multimeter for accurate readings.

Tip: Compare measured voltages with schematic values ±10% tolerance.

Troubleshooting Guide

Systematic troubleshooting approach for common problems.

1. No Power: Check AC input, fuse, power switch, transformer
2. No Reception: Verify antenna connection, RF stages, local oscillator
3. Poor Sensitivity: Test RF amplifier, mixer, IF stages
4. Frequency Drift: Check PLL lock, VCO stability, reference oscillator
5. Distorted Audio: Test audio stages, speakers, power supply
6. Display Issues: Verify display driver, segment outputs, backlight
7. Control Problems: Check encoder, switches, control processor
8. Intermittent Operation: Inspect for cold solder joints, connector issues

WARNING! Always disconnect power before internal inspection.

Parts List

Complete component listing with manufacturer part numbers.

Schematic Diagrams

Detailed schematic diagrams for all circuit sections.

CAUTION! Schematics contain proprietary information for authorized service only.

Service Notes

Factory service bulletins and technical updates.

Reset: Power cycle and factory reset procedure if available.

Service Support: Contact Kenwood authorized service centers for technical assistance.