Kenwood TS-950SDX Service Manual

The Kenwood TS-950SDX is a high-performance HF transceiver featuring advanced DSP technology, 100W output power, comprehensive receiver and transmitter sections, built-in antenna tuner, and extensive connectivity options. This service manual provides detailed technical information for maintenance, repair, and adjustment procedures. Below are key sections covering specifications, block diagrams, alignment procedures, circuit descriptions, and troubleshooting.

1. Technical Specifications 2. Block Diagrams 3. Alignment Procedures 4. Circuit Descriptions 5. Disassembly Instructions 6. Test Points & Measurements 7. Parts List 8. PCB Layouts 9. Troubleshooting Guide 10. Schematics 11. Service Notes

Technical Specifications

Complete technical specifications for the Kenwood TS-950SDX transceiver system.

Parameter	Specification
Frequency Range	1.8-30 MHz (all amateur bands)
Mode	SSB, CW, AM, FM, FSK
Output Power	100W PEP (SSB), 100W DC (CW)
Receiver Sensitivity	0.15μV for 10dB S+N/N
IF Bandwidth	2.4kHz, 500Hz, 250Hz (selectable)
Power Supply	13.8V DC ±15%
Current Consumption	Receive: 2A, Transmit: 22A max
Dimensions	420(W) x 145(H) x 380(D) mm
Weight	Approx. 15 kg
IF Frequencies	1st: 69.0115 MHz, 2nd: 8.83 MHz

Block Diagrams

System block diagrams showing signal flow and major components.

Overall System Block Diagram: Shows complete signal path from antenna to audio.
Receiver Block Diagram: Detailed RF/IF/AF signal processing chain.
Transmitter Block Diagram: Exciter, PA, and control circuits.
DSP Section Block Diagram: Digital signal processing flow.
Power Supply Block Diagram: Voltage regulation and distribution.

NOTE! Refer to schematics for detailed component-level information.

Alignment Procedures

Step-by-step alignment procedures for optimal performance.

Receiver Alignment: RF front-end, IF stages, and detector circuits.
Transmitter Alignment: Exciter levels, PA bias, and ALC settings.
VCO Alignment: PLL and synthesizer voltage-controlled oscillators.
Filter Alignment: Crystal and mechanical filter adjustments.
DSP Alignment: Digital processing parameters and calibration.

CAUTION! Use proper test equipment and follow safety procedures.

Circuit Descriptions

Receiver Section: Front-end preselector, mixer, IF amplification, detector circuits.
Transmitter Section: Modulator, driver stages, final amplifier, ALC system.
Synthesizer Section: PLL circuits, VCOs, reference oscillators.
DSP Section: Digital filtering, noise reduction, audio processing.
Control Section: Microprocessor, display, and interface circuits.
Power Supply: Switching regulator, voltage protection circuits.
Antenna Tuner: Automatic impedance matching network.

Disassembly Instructions

Step-by-step disassembly procedures for service access.

Front Panel Removal: Remove knobs, screws, and carefully disconnect ribbon cables.

Main Unit Disassembly: Remove covers, shieldings, and module connectors.

Power off and disconnect all cables.
Remove top and bottom covers.
Document cable positions before disconnection.
Remove required modules for component access.
Handle PCBs with care to avoid static damage.

WARNING! High voltages present - discharge capacitors before servicing.

Test Points & Measurements

Critical test points and expected voltage/waveform measurements.

Test Point	Location	Normal Value
TP1 (B+)	Power Supply	+13.8V DC
TP2 (ALC)	PA Board	0-5V DC (transmit)
TP3 (PLL Lock)	Synthesizer	+5V DC (locked)
TP4 (Audio Out)	AF Board	1V RMS (1kHz tone)
TP5 (RF Drive)	Driver Stage	10W PEP (SSB)

Parts List

Complete component listing with part numbers and descriptions.

Semiconductors: Transistors, ICs, diodes with manufacturer part numbers.
Passive Components: Resistors, capacitors, inductors with values and tolerances.
Mechanical Parts: Hardware, connectors, knobs, and fasteners.
PCB Assemblies: Complete board part numbers for replacement.
Special Components: Crystals, filters, and custom parts.

Tip: Verify part numbers before ordering replacements.

PCB Layouts

Printed circuit board layouts for all major assemblies.

Includes component placement, trace routing, and layer information for:

Main Board Assembly
Front Panel Board
RF Unit Board
Power Supply Board
DSP Module Board
Antenna Tuner Board

NOTE! Use layouts with schematics for proper troubleshooting.

Troubleshooting Guide

Symptom	Possible Cause	Corrective Action
No power	Power supply fault	Check fuse F1, regulator IC, input voltage
No transmit	PA fault, ALC issue	Check final transistors, ALC voltage, driver stages
Poor receiver sensitivity	RF amp, mixer fault	Check front-end transistors, bias voltages
Frequency instability	PLL unlock, VCO drift	Check reference oscillator, VCO tuning voltages
Display problems	Display driver, CPU	Check ribbon cables, display voltages, CPU operation

Reset Procedure: Power cycle and check for error codes.

Schematics

Complete schematic diagrams for all circuit sections.

Power Supply Schematic: Voltage regulation and protection circuits.
Receiver Schematic: RF through audio amplification stages.
Transmitter Schematic: Modulation through power amplifier.
Control Schematic: Microprocessor and interface circuits.
Synthesizer Schematic: PLL and frequency generation.
DSP Schematic: Digital signal processing circuits.

WARNING! High voltage areas marked - observe safety precautions.

Service Notes

Important service information and technical updates.

Factory Adjustments: Critical alignment points and procedures.
Common Failures: Known component failures and recommended replacements.
Modification Notes: Factory modifications and upgrades.
Calibration Data: Reference settings and calibration values.
Service Bulletins: Technical updates and service advisories.

Service Contact: Authorized Kenwood service centers only.