Marantz SR4023 Service Manual

The Marantz SR4023 is a high-performance audio/video receiver featuring Dolby Digital and DTS decoding, 5.1 channel surround sound, multiple audio/video inputs, AM/FM tuner, remote control, and advanced audio processing. This service manual provides comprehensive technical information for service technicians, including schematics, alignment procedures, troubleshooting guides, and replacement parts information.

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

Technical Specifications

Complete technical specifications and performance characteristics of the Marantz SR4023 receiver.

Parameter	Specification
Power Output	80W x 5 channels (8 ohms, 20Hz-20kHz)
Total Harmonic Distortion	0.08% (20Hz-20kHz)
Frequency Response	10Hz-100kHz (+1/-3dB)
Signal-to-Noise Ratio	100dB (line input)
Input Sensitivity	200mV (line), 2.5mV (phono)
Digital Inputs	2 optical, 2 coaxial
Analog Inputs	6 line, 1 phono, 1 tape
Video Inputs	3 composite, 2 S-video
Outputs	5.1 channel pre-out, tape out, video out
Power Consumption	450W maximum

Block Diagrams

System block diagrams showing signal flow and functional relationships between circuit sections.

Main System Block Diagram: Overview of entire receiver architecture
Audio Processing Block Diagram: Digital audio signal path
Power Supply Block Diagram: Voltage regulation and distribution
Tuner Section Block Diagram: AM/FM reception circuitry
Video Processing Block Diagram: Video signal routing

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

Circuit Descriptions

Detailed descriptions of major circuit sections and their operation.

Power Supply Circuit: Switching power supply with multiple voltage outputs
Main Amplifier Circuit: 5-channel power amplifier section
Digital Audio Processor: Dolby Digital and DTS decoding
Tuner Circuit: PLL synthesized AM/FM tuner
Microprocessor Control: System control and user interface
Input/Output Switching: Audio/video input selection matrix

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

Disassembly Instructions

Step-by-step instructions for disassembling the receiver for service access.

Remove top cover: Remove 6 screws from rear panel and 2 from sides
Remove front panel: Disconnect ribbon cables and remove 4 screws
Access main board: Remove shield covers and disconnect wiring harnesses
Remove power supply: Disconnect all connectors and remove mounting screws
Access tuner module: Remove RF connectors and module mounting screws

CAUTION! Document cable positions and connector orientations during disassembly.

Alignment Procedures

Factory alignment procedures for optimal performance.

FM Tuner Alignment: IF alignment, oscillator tracking, stereo decoder
AM Tuner Alignment: IF alignment, oscillator tracking
Audio Alignment: Channel balance, frequency response adjustment
Power Supply: Voltage calibration and current limit adjustment
Protection Circuit: DC offset and overcurrent protection calibration
Digital Processor: Clock alignment and digital filter settings

Troubleshooting Guide

Systematic troubleshooting procedures for common service issues.

Symptom	Possible Cause	Corrective Action
No power	Power supply failure	Check fuse F001, test switching transistors Q001-Q003
No audio output	Amplifier section	Test output transistors, check protection circuit
Distorted audio	DC offset	Measure DC offset at speaker terminals, replace faulty components
No display	Front panel circuit	Check display driver IC, test microprocessor
Remote not working	IR receiver	Test IR receiver module, check 5V supply
Overheating	Bias current	Adjust bias current, check heatsink contact

Parts List

Complete list of replacement parts with manufacturer part numbers.

Part Number	Description	Qty
IC001	Main Microprocessor	1
IC101	Digital Audio Processor	1
Q201-Q205	Output Transistors	10
F001	Main Fuse 5A	1
C101	Main Filter Capacitor	1
TR001	Power Transformer	1
J101	Input Selector Relay	1

Schematics

Complete circuit schematics for all major sections.

Main System Schematic: Overall system interconnections
Power Supply Schematic: Detailed power supply circuitry
Amplifier Schematic: 5-channel power amplifier circuits
Digital Audio Schematic: Audio processing and decoding
Tuner Schematic: AM/FM tuner circuits
Control Schematic: Microprocessor and control circuits

NOTE: Schematics show component values and test points for service.

PCB Layouts

Printed circuit board layouts showing component placement and routing.

Main Board: Component side and solder side views
Power Supply Board: Component placement and heatsink mounting
Front Panel Board: Display and control button layout
Tuner Module: RF circuit component placement
Amplifier Section: Output stage component layout

Tip: Use layouts for component location and trace routing identification.

Safety Precautions

Essential safety procedures for service technicians.

Always disconnect AC power before servicing. Use isolation transformer when testing live circuits. Discharge large capacitors before handling. Use appropriate personal protective equipment. Follow ESD precautions when handling semiconductors.

WARNING! Lethal voltages present in power supply section. Only qualified technicians should perform service.

Service Notes

Important service tips and factory updates.

Service Bulletin	Description	Date
SB-4023-001	Updated bias adjustment procedure	03/2005
SB-4023-002	Replacement output transistor specifications	06/2005
SB-4023-003	Improved heatsink compound application	09/2005
SB-4023-004	Microprocessor firmware update procedure	12/2005

Service Support: Contact Marantz technical support for latest service information and parts availability.