Kenwood TM D700 Service Manual

The Kenwood TM D700 is a dual-band FM transceiver designed for amateur radio use, featuring 2m/70cm operation, cross-band repeating capability, built-in TNC for packet communication, multiple memory channels, CTCSS/DCS encode/decode, and robust construction for mobile/base station applications. Below are key sections for technical specifications, disassembly procedures, circuit descriptions, alignment instructions, troubleshooting, and parts lists.

1. Technical Specifications 2. Disassembly Procedures 3. Circuit Descriptions 4. Alignment Instructions 5. Block Diagrams 6. Schematic Diagrams 7. PCB Layouts 8. Troubleshooting Guide 9. Parts List 10. Service Notes 11. Firmware Information

Technical Specifications

Key technical parameters and operating characteristics of the Kenwood TM D700 transceiver.

Parameter	Specification
Frequency Range	144-148 MHz (2m), 430-450 MHz (70cm)
Mode	FM
RF Power Output	50W (2m), 35W (70cm) - High; 5W - Low
Voltage Requirement	13.8V DC ±15%
Current Consumption	Receive: 0.6A (max audio); Transmit: 12A (2m high power)
Sensitivity	0.16μV (12dB SINAD)
Selectivity	12kHz (-6dB), 24kHz (-60dB)
Audio Output	2W into 8Ω at 10% distortion
Memory Channels	200 regular + 6 scan edges
Dimensions	140(W) × 45(H) × 180(D) mm

Disassembly Procedures

Step-by-step instructions for safely disassembling the transceiver for service and repair.

Remove top and bottom covers: Unscrew 6 Phillips screws from bottom case.
Separate front panel: Disconnect ribbon cable from main board carefully.
Remove main board: Detach all connectors and unscrew mounting screws.
Access RF unit: Remove shield covers for transmitter and receiver sections.
Remove display assembly: Detach LCD connector and remove mounting screws.

WARNING! Always disconnect power before disassembly. Use anti-static precautions when handling PCBs.

Circuit Descriptions

Detailed explanation of major circuit blocks and their functions.

Receiver Section: Double conversion superheterodyne with 45.05MHz and 455kHz IFs.
Transmitter Section: PLL synthesized exciter with multi-stage RF power amplifier.
PLL Circuit: TC9122P synthesizer IC with 5.12MHz reference oscillator.
Audio Processing: Includes compander, CTCSS/DCS encode/decode, and audio filtering.
Power Supply: Built-in voltage regulation and protection circuits.
TNC Section: Built-in packet controller for data communication.

NOTE: Refer to schematic diagrams for component-level details.

Alignment Instructions

Factory alignment procedures requiring proper test equipment.

PLL Adjustment: Adjust VC1 for zero beat at center frequency.
Receiver Alignment: Adjust L1, L2 for maximum sensitivity at 146MHz/446MHz.
Transmitter Alignment: Adjust driver and final amplifier for specified power output.
Modulation Balance: Set deviation for 5kHz with 1kHz tone.
CTCSS Alignment: Adjust sub-audible tone frequency and level.
S-meter Calibration: Calibrate using standard signal generator.

Block Diagrams

System-level block diagrams showing signal flow and major components.

Includes: Overall system block diagram, Receiver block diagram, Transmitter block diagram, PLL synthesizer block diagram, Audio processing block diagram, Power supply block diagram, TNC interface block diagram.

Reference: See schematic package for detailed interconnections.

Schematic Diagrams

Complete schematic diagrams for all circuit sections.

Main Unit Schematic: Shows complete receiver/transmitter circuitry.
Power Supply Schematic: Voltage regulation and protection circuits.
Front Panel Schematic: Display, controls, and interface circuits.
TNC Section Schematic: Packet data interface and modem.
RF Unit Schematic: VCO, PA, and filter networks.

CAUTION! High voltages present in transmitter section. Exercise caution during testing.

PCB Layouts

Printed circuit board layouts for component placement and trace routing.

Main Board Top Layer: Component placement and signal traces.
Main Board Bottom Layer: Ground plane and additional routing.
Front Panel Board: Control and display interface.
RF Board: Transmitter and receiver RF circuits.
Power Supply Board: Voltage regulation components.

Troubleshooting Guide

Systematic approach to diagnosing and repairing common problems.

Symptom	Possible Cause	Corrective Action
No power	Blown fuse, faulty power connector	Check F1 (10A), verify 13.8V at power input
No transmit	PA failure, PLL unlock	Check Q15-Q17, verify PLL lock voltage
Poor reception	Front-end damage, alignment	Check Q1-Q3, realign receiver front-end
Display problems	Ribbon cable, LCD failure	Reseat CN1, check LCD contrast voltage
No audio	Audio IC failure, speaker	Check IC8 (audio amp), verify speaker continuity
TNC not working	Interface cable, TNC settings	Verify cable connections, check TNC configuration

Parts List

Complete listing of components with part numbers and specifications.

Includes: ICs and semiconductors, Transistors and diodes, Resistors and capacitors, Inductors and transformers, Mechanical parts, Connectors and hardware.

Note: Use genuine Kenwood parts for replacements to ensure performance and reliability.

Service Notes

Important service information and technical bulletins.

Common issues: PLL unlock problems often caused by faulty varactor diodes D1/D2. Transmitter power drop typically due to failed final transistors Q16/Q17. Display fading usually requires LCD replacement.

Service Advisory: Always check for latest service bulletins before repair.

Firmware Information

Microprocessor and TNC firmware details and update procedures.

Main CPU: HD64F3346F28 with system control firmware
TNC Processor: Dedicated controller for packet operations
Firmware Version: Check via service mode entry
Update Procedure: Requires factory programming equipment
EEPROM Data: Contains calibration and configuration data

WARNING! Firmware updates should only be performed by authorized service personnel.