kenwood ts 440s service manual pdf

The Kenwood TS-440S is an amateur radio transceiver covering HF bands with SSB, CW, AM, and FM modes. This service manual provides comprehensive technical information for maintenance, repair, and adjustment procedures. Below are key sections covering specifications, block diagrams, alignment procedures, troubleshooting, and circuit descriptions.

1. General Specifications 2. Technical Features 3. Block Diagram Overview 4. Alignment Procedures 5. Circuit Descriptions 6. Troubleshooting Guide 7. Parts List 8. PCB Layouts 9. Voltage Charts 10. Service Adjustments 11. Schematic Diagrams

General Specifications

The TS-440S operates on all amateur bands from 1.8 to 30 MHz with 100W output power.

Parameter	Specification
Frequency Coverage	1.8-30 MHz (all amateur bands)
Modes	SSB, CW, AM, FM
Output Power	100W PEP (SSB), 100W (CW)
Receiver Sensitivity	0.25μV for 10dB S+N/N
Power Supply	13.8V DC ±15%
Current Drain	Receive: 1.3A, Transmit: 20A max
Dimensions	240W × 95H × 300D mm
Weight	5.5 kg
IF Frequencies	1st: 69.0115MHz, 2nd: 8.83MHz, 3rd: 455kHz

Technical Features

Key technical components and features of the TS-440S transceiver.

Feature	Description
VFO System	Dual VFOs with 10Hz step resolution
Memory Channels	40 programmable memory channels
IF Filter	8-pole crystal filter (2.4kHz SSB)
AGC System	Fast/slow AGC selectable
Antenna Tuner	Built-in automatic antenna tuner (AT-440)
Digital Display	LCD with S/RF meter and function indicators
Connectors	MIC, PHONES, CW KEY, ANT, DC IN
Optional Units	AT-440 tuner, SP-440 external speaker

Block Diagram Overview

Understanding the signal flow through the transceiver system.

Receiver Section: RF amplifier → 1st mixer → 1st IF (69.0115MHz) → 2nd mixer → 2nd IF (8.83MHz) → 3rd mixer → 3rd IF (455kHz) → detector → audio amplifier
Transmitter Section: Microphone amplifier → balanced modulator → 1st IF → mixer → driver → power amplifier
Frequency Synthesis: TCXO reference → PLL system → VCO → buffer amplifiers

NOTE: All alignment should be performed with proper test equipment and following exact procedures.

Alignment Procedures

Step-by-step alignment instructions for optimal performance.

Receiver Alignment: Adjust RF amplifier coils for maximum sensitivity
IF Alignment: Align 69.0115MHz and 8.83MHz IF stages
PLL Adjustment: Set VCO lock range and reference frequency
Transmitter Alignment: Adjust driver and PA stages for proper output
AGC Alignment: Set AGC time constants and threshold levels
Filter Alignment: Adjust crystal filter matching networks

WARNING! Use calibrated test equipment and follow safety procedures when working with high voltages.

Circuit Descriptions

Detailed explanation of major circuit blocks and their functions.

RF Unit: Contains RF amplifier, antenna relay, and input filtering
IF Unit: Main IF processing with crystal filters and amplifiers
PLL Unit: Frequency synthesis system with VCO and dividers
Audio Unit: Microphone amplification, audio filtering, and speaker output
Control Unit: Microprocessor control system and display driver
Power Supply: Voltage regulation and distribution circuits

Troubleshooting Guide

Common problems and their solutions for the TS-440S.

Symptom	Possible Cause	Corrective Action
No power	Power supply fault	Check DC input, fuses F1-F3, regulator ICs
No transmit	PA fault or relay issue	Check TR21-TR24, antenna relay RL1
Poor reception	RF amplifier fault	Check TR1-TR3, alignment of RF stages
Frequency drift	TCXO or PLL fault	Check X1 (TCXO), PLL lock voltage
No display	Control unit fault	Check IC19 (CPU), display connections
Low power output	Driver or PA bias	Adjust VR10 (carrier), check TR21-TR24

Parts List

Essential replacement parts and components for service.

Part Number	Description	Qty
X06-1250-01	Main PCB Assembly	1
X09-1130-01	Front Panel Assembly	1
2SC2879	Final PA Transistor	4
LA2730	IF Amplifier IC	1
MB1501	PLL IC	1
F1-F3	Fuse 8A, 5A, 3A	3
RL1	Antenna Relay	1

PCB Layouts

Printed circuit board layouts and component locations.

Main Unit PCB: Component side and solder side diagrams
Control Unit PCB: Display and keyboard interface layout
RF Unit PCB: RF amplifier and filter component placement
PLL Unit PCB: VCO and synthesizer component locations

NOTE: Refer to actual service manual for detailed PCB diagrams and component identifications.

Voltage Charts

DC voltage measurements at test points for troubleshooting.

Test Point	Voltage (DC)	Condition
TP1 (13.8V)	13.8V ±0.5V	Power on
TP2 (8V)	8.0V ±0.2V	Receive mode
TP3 (5V)	5.0V ±0.1V	All modes
TP4 (PLL Vt)	2-10V	Varies with frequency
TP5 (AGC)	0.5-8V	Varies with signal

Service Adjustments

Critical adjustments requiring special attention during service.

Carrier Suppression: Adjust VR5 for minimum carrier leakage
SSB Balance: Adjust VR6 for proper sideband suppression
PA Bias: Set VR10 for proper quiescent current
ALC Level: Adjust VR11 for proper ALC operation
S-meter Calibration: Adjust VR12 for accurate S-meter reading
Power Output: Verify and adjust for 100W PEP maximum

CAUTION! These adjustments require proper test equipment and should only be performed by qualified technicians.

Schematic Diagrams

Complete schematic diagrams for all circuit sections.

Main Receiver/Transmitter Schematic
Power Supply Schematic
PLL Synthesizer Schematic
Control Unit Schematic
RF Unit Schematic
Audio Unit Schematic

Service Support: For technical assistance contact Kenwood authorized service centers or visit www.kenwood.com