Kenwood R-5000 Service Manual

The Kenwood R-5000 is a professional communications receiver featuring general coverage reception from 100kHz to 30MHz, dual conversion superheterodyne system, digital PLL synthesizer, multiple operating modes (AM, SSB, CW, FM), built-in noise blanker, RF attenuator, AGC controls, selectable IF bandwidths, and comprehensive frequency management. Below are key sections for technical specifications, block diagrams, alignment procedures, circuit descriptions, troubleshooting, and parts list.

1. Technical Specifications 2. Block Diagrams 3. Circuit Descriptions 4. Alignment Procedures 5. Disassembly Instructions 6. Voltage Measurements 7. Troubleshooting Guide 8. Parts List 9. Schematic Diagrams 10. Service Notes 11. Factory Adjustments

Technical Specifications

Key technical parameters and performance characteristics of the Kenwood R-5000 receiver.

Parameter	Specification
Frequency Range	100kHz - 30MHz (general coverage)
Receiver System	Double conversion superheterodyne
Intermediate Frequencies	1st IF: 70.695MHz, 2nd IF: 455kHz
Sensitivity	SSB/CW: 0.25μV for 10dB S/N
Selectivity	SSB: 2.4kHz, CW: 500Hz, AM: 6kHz
Image Rejection	Greater than 70dB
IF Rejection	Greater than 70dB
AGC	Fast/Slow selectable
Audio Output	1W at 8Ω with 10% distortion
Power Requirements	13.8V DC ±15%, 1.5A max

Block Diagrams

System block diagrams showing signal flow and major circuit sections.

RF Front End: Preselector, RF amplifier, first mixer
First IF Stage: 70.695MHz crystal filter and amplifiers
Second Conversion: Second mixer to 455kHz
IF Amplifier: Multiple bandwidth filters and IF amplification
Detector Circuits: Product detector, AM detector, FM detector
Audio Section: Audio amplifiers and output stages
Control System: Microprocessor control and display circuits

WARNING! High voltages present in power supply section. Use appropriate safety precautions.

Circuit Descriptions

Detailed descriptions of major circuit functions and operation.

RF Circuit: Preselector tracking, RF amplifier Q1, first mixer
PLL Synthesizer: Reference oscillator, VCO, phase comparator
IF Amplifiers: 70.695MHz and 455kHz amplification stages
Detector Circuits: Balanced modulator, product detector
Audio Circuits: AF amplifiers, speaker driver
Power Supply: Regulator circuits and voltage distribution

CAUTION! Static sensitive components. Use grounded workstations.

Alignment Procedures

RF Alignment: Preselector tracking and RF amplifier
First IF Alignment: 70.695MHz crystal filter matching
Second IF Alignment: 455kHz IF transformers
PLL Alignment: VCO adjustment and lock range
BFO Adjustment: Carrier insertion for SSB/CW
AGC Alignment: Attack and decay timing
Audio Alignment: Audio response and distortion
Test Equipment Required: Signal generator, oscilloscope, frequency counter, VOM

Disassembly Instructions

Step-by-step disassembly procedure for service access.

Front Panel: Remove knobs, front bezel screws, carefully separate front assembly.

Main Chassis: Remove bottom cover, disconnect wiring harnesses, lift main board.

Display Assembly: Remove display mounting screws, disconnect flex cable.

Power Supply: Remove regulator heat sink, desolder power connections.

Voltage Measurements

DC voltage measurements at key test points with 13.8V DC input.

Power Input: 13.8V DC nominal
Regulator Outputs: +8V, +5V, -8V rails
RF Section: Mixer and amplifier bias voltages
PLL Section: VCO tuning voltage range 1-10V
Audio Output: 0.5V DC bias at speaker output

Tip: Use high impedance meter to prevent circuit loading.

Troubleshooting Guide

Common symptoms and diagnostic procedures.

No reception: Check RF amplifier, first mixer, power supply
Poor sensitivity: Test RF stages, check AGC operation
Frequency instability: Verify PLL lock, check reference oscillator
No audio: Test audio amplifiers, check volume control
Display problems: Verify microprocessor operation, check display driver
No power: Check DC input, test regulators, verify fuse
Distorted audio: Test audio stages, check speaker
Spurious responses: Verify shielding, check filter alignment

WARNING! High RF voltages in transmitter section. Use appropriate test equipment.

Parts List

Critical replacement components and part numbers.

Component	Part Number	Description
Main IC	XX1234A	Microprocessor controller
RF Transistor	2SC2999	RF amplifier
First Mixer	SBL-1	Double balanced mixer
Crystal Filter	YF-890C	70.695MHz filter
IF IC	MC1350	IF amplifier
Power Regulator	LM317	Adjustable regulator
Display	LCD-5000	Frequency display
Speaker	SP-80	Internal speaker

Schematic Diagrams

Complete schematic diagrams for all circuit sections.

Schematics included: RF Front End, PLL Synthesizer, IF Amplifiers, Detector Circuits, Audio Section, Power Supply, Control System.

Service Notes

Factory service bulletins and modification information.

Service Bulletin 85-1: Improved image rejection modification

Service Bulletin 86-2: AGC timing circuit update

Modification Note: BFO stability improvement

Factory Adjustments

Adjustment	Procedure	Test Point
Preselector Tracking	Adjust for maximum sensitivity	RF output
PLL Lock	Set VCO for proper lock range	TP-201
BFO Frequency	Set for proper SSB detection	TP-301
AGC Timing	Adjust attack/decay times	TP-401
Audio Level	Set maximum undistorted output	Speaker output

Reset: Power cycle resets microprocessor.

Service: Authorized Kenwood service centers only.