Kenwood TS-700A Service Manual

The Kenwood TS-700A is a 2-meter amateur radio transceiver featuring all-mode operation (FM/SSB/CW), 10-watt output power, built-in power supply, synthesized frequency control, and comprehensive receiver/transmitter circuits. This service manual covers technical specifications, circuit descriptions, alignment procedures, troubleshooting, and maintenance guidelines for qualified service technicians.

1. Technical Specifications 2. Block Diagram Overview 3. Circuit Descriptions 4. Alignment Procedures 5. Voltage Measurements 6. Troubleshooting Guide 7. Parts List 8. Schematic Diagrams 9. Mechanical Assembly 10. Service Notes

Technical Specifications

Complete electrical and mechanical specifications for the Kenwood TS-700A transceiver.

ParameterSpecification
Frequency Range144-148 MHz (2-meter band)
ModesFM, SSB, CW
Output Power10 watts (FM), 8 watts (SSB/CW)
Power Supply13.8V DC ±15%
Current DrainReceive: 0.8A, Transmit: 2.5A max
Sensitivity0.25μV for 12dB SINAD (FM)
Selectivity±7 kHz at -6dB (FM)
Dimensions240(W) × 85(H) × 240(D) mm
Weight3.2 kg
Antenna ConnectorSO-239 (UHF female)

Block Diagram Overview

System block diagram showing major circuit sections and signal flow.

  1. RF Unit: Front-end filtering and pre-amplification
  2. IF Unit: 10.7 MHz and 455 kHz IF stages
  3. PLL Synthesizer: Frequency generation and control
  4. Audio Unit: Microphone preamp and audio output
  5. Power Supply: Built-in 13.8V regulation
  6. Control Unit: Microprocessor and interface circuits

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

Circuit Descriptions

Detailed description of major circuit sections and their operation.

  1. Receiver Section: Dual conversion superheterodyne with crystal filter
  2. Transmitter Section: Balanced modulator and RF power amplifier
  3. PLL Circuit: TC-9122P IC with 6.4 MHz reference
  4. Audio Circuits: LM386 audio amplifier IC
  5. Power Supply: 7808 and 7812 voltage regulators

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

Alignment Procedures

Voltage Measurements

Reference voltage measurements at key test points.

Test PointVoltage (DC)Condition
IC1 Pin 14+8VReceive mode
Q7 Collector+13.8VTransmit mode
TP1+5VPLL reference
TP2+12VAudio section
VR1 Center0-5V adjustableSquelch control

Troubleshooting Guide

Common symptoms and corrective actions for the TS-700A.

SymptomPossible CauseCorrective Action
No powerPower supply faultCheck F1 fuse, Q8 regulator, D1-D4 diodes
No receiveRF/IF circuit faultCheck Q1-Q3, IC2, crystal filters
No transmitPA circuit faultCheck Q5-Q6, driver stage, TR relay
Frequency driftPLL unlockAdjust VCO coil L10, check TC-9122P
Poor sensitivityFront-end faultCheck RF amp Q1, alignment

Reset: Power cycle unit; check all connections.

Parts List

Critical replacement components and part numbers.

  1. IC1: TC-9122P (PLL IC)
  2. IC2: MC3357P (FM IF)
  3. Q5: 2SC2166 (Driver transistor)
  4. Q6: 2SC1307 (Final transistor)
  5. F1: 3A fuse
  6. X1: 6.4 MHz reference crystal

Tip: Use genuine Kenwood parts for optimal performance.

Schematic Diagrams

Complete schematic diagrams for all circuit sections.

  1. Main board schematic (page 1-4)
  2. RF unit schematic (page 5)
  3. Power supply schematic (page 6)
  4. Control unit schematic (page 7)
  5. Wiring diagram (page 8)

WARNING! Schematics contain high-voltage areas. Follow safety procedures.

Mechanical Assembly

Disassembly and reassembly instructions with exploded views.

Service Notes

Important service information and technical bulletins.

FCC ID: ALH29903270. Service only by qualified technicians. For technical support, contact authorized Kenwood service centers. Original documentation copyright Kenwood Corporation. All specifications subject to change without notice.

Kenwood TS-700A Service Manual © - All Rights Reserved 2025