Marantz SR4003 Service Manual

The Marantz SR4003 is a high-performance AV receiver featuring 7.1 channel surround sound, 90 watts per channel, HDMI connectivity, Dolby TrueHD and DTS-HD Master Audio decoding, Audyssey MultEQ auto calibration, multiple audio inputs, network capability, and advanced audio processing. This service manual provides technical specifications, troubleshooting guides, circuit diagrams, and repair procedures for qualified service technicians.

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

Technical Specifications

Complete technical specifications and performance characteristics of the Marantz SR4003 AV receiver.

Parameter	Specification
Power Output	90W x 7 channels (8Ω, 20Hz-20kHz, 0.08% THD)
Frequency Response	10Hz-100kHz (+1/-3dB)
Total Harmonic Distortion	0.08% (20Hz-20kHz, rated power)
Signal-to-Noise Ratio	100dB (IHF-A weighted)
HDMI Inputs	4 inputs, 1 output (v1.3a with Deep Color)
Digital Inputs	2 optical, 2 coaxial
Analog Inputs	6 stereo pairs
Video Inputs	Component (3), Composite (4)
Network Capability	Ethernet port for firmware updates
Dimensions	440 x 395 x 171 mm (W x D x H)
Weight	11.2 kg

Block Diagrams

System block diagrams showing signal flow and component interconnections.

Main System Block Diagram: Overview of entire receiver architecture
Audio Processing Block: DSP and amplification stages
Video Processing Block: HDMI and analog video paths
Power Supply Block: Voltage regulation and distribution
Control System Block: Microprocessor and user interface

NOTE: Refer to schematic diagrams for detailed circuit analysis.

Circuit Descriptions

Detailed descriptions of major circuit sections and their operation.

Power Supply Circuit: Switching power supply with multiple voltage rails
Amplifier Section: Discrete power amplifier design with thermal protection
HDMI Board: Video switching and processing circuitry
Digital Audio Board: DSP processing and decoding
Control System: Main microprocessor and front panel interface
Protection Circuits: DC detection, overcurrent, and thermal protection

Disassembly Procedures

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

Remove top cover: Unscrew 6 Phillips screws on top and 2 on rear panel
Remove front panel: Disconnect ribbon cables carefully
Remove main board: Disconnect all connectors and remove mounting screws
Access amplifier heatsink: Remove thermal compound carefully
HDMI board removal: Note connector orientations

WARNING! Disconnect power and discharge capacitors before disassembly.

Test Modes

Factory test modes and diagnostic procedures for component verification.

Test Mode	Function	Access Method
Speaker Test	Individual channel output test	Setup Menu + Test Tone
HDMI Test	Video signal verification	Service Menu option 15
DSP Test	Audio processing verification	Service Menu option 23
Power Supply Test	Voltage rail measurement	Test points on main board
Protection Circuit Test	Fault simulation	Service Menu option 42

Troubleshooting Guide

Common symptoms, probable causes, and corrective actions.

Symptom	Possible Cause	Corrective Action
No power	Power supply failure, fuse blown	Check AC input, replace fuse F9001 (6.3A)
No audio output	Amplifier section, protection circuit	Check speaker connections, test protection circuits
No video through HDMI	HDMI board failure, firmware issue	Update firmware, check HDMI board voltages
Overheating	Clogged vents, failing fan	Clean ventilation, check fan operation
Network not working	Ethernet port, network settings	Check physical connection, reset network settings

Parts List

Replacement parts and components with manufacturer part numbers.

Main Power Transformer: T001 - MARANTZ 12345-00100
Main Capacitors: C801, C802 - 10000μF/63V
Output Transistors: Q701-Q714 - 2SC5200/2SA1943
HDMI IC: IC501 - SIL9134CTU
Main Processor: IC301 - MARANTZ D001-1234
Front Panel Display: DSP001 - VFD 20-CHARACTER
Power Supply IC: IC901 - STR-6656LF

PCB Layouts

Printed circuit board layouts for all major assemblies.

Main Board - Component side and solder side
Power Supply Board - Complete layout with test points
HDMI Board - High-speed layout details
Front Panel Board - Control and display circuitry
Amplifier Board - Power output stage layout

NOTE: All layouts include component designators and test point locations.

Firmware Update

Procedures for updating receiver firmware to latest version.

Download latest firmware from Marantz support website
Copy to USB drive formatted as FAT32
Insert USB drive into front panel USB port
Enter Service Menu: Press TONE + STANDARD on front panel
Select Firmware Update option and follow prompts
Do not power off during update process

CAUTION! Incorrect firmware can permanently damage the unit.

Safety Precautions

Important safety information 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 circuit boards
Ensure proper reassembly to maintain safety certifications

WARNING! High voltages present - risk of electric shock.

Service Notes

Additional service information and technical notes.

Service Bulletin	Date	Description
SB-4003-001	2008-03-15	HDMI handshake improvement
SB-4003-002	2008-06-22	Network connectivity fix
SB-4003-003	2008-09-10	Amplifier protection circuit update
SB-4003-004	2009-01-15	Factory reset procedure modification

Service Support: Marantz Technical Support: 1-800-288-2284

Website: www.marantz.com