Marantz SR8500 Service Manual

The Marantz SR8500 is a high-performance AV receiver featuring 7.1 channel surround sound, Dolby Digital and DTS decoding, 120W per channel power output, multiple audio/video inputs, digital optical/coaxial inputs, AM/FM tuner, preamp outputs, and advanced audio calibration. This service manual provides technical specifications, troubleshooting procedures, circuit diagrams, and repair guidelines for qualified service technicians.

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

Technical Specifications

Complete technical specifications and performance characteristics of the Marantz SR8500 AV receiver.

ParameterSpecification
Power Output120W x 7 channels (8Ω, 20Hz-20kHz, 0.08% THD)
Frequency Response10Hz - 100kHz (+1/-3dB)
Total Harmonic Distortion0.08% (20Hz-20kHz at rated power)
Signal-to-Noise Ratio100dB (IHF-A)
Input Sensitivity200mV (line), 2.5mV (MM phono)
Digital InputsOptical x 3, Coaxial x 3
Video InputsComposite x 6, S-Video x 4, Component x 3
Audio InputsAnalog x 8, Phono x 1
Outputs7.1 preamp, Zone 2, composite/S-video monitor
Power Consumption650W maximum, 85W standby

Block Diagrams

System block diagrams showing signal flow and functional relationships between major components.

  1. Main System Block Diagram: Overall signal processing flow
  2. Power Supply Block Diagram: AC/DC conversion and distribution
  3. Audio Processing Block Diagram: DAC/ADC and DSP signal paths
  4. Video Processing Block Diagram: Video switching and conversion
  5. Control System Block Diagram: Microprocessor and interface control

WARNING! These diagrams are for reference only. Always verify actual circuit conditions before servicing.

Circuit Descriptions

Detailed descriptions of major circuit sections and their operation.

  1. Power Supply Circuit: Switching power supply with multiple voltage rails
  2. Main Amplifier Circuit: 7-channel discrete power amplifier design
  3. Digital Audio Circuit: 24-bit/192kHz DAC and digital processing
  4. Video Circuit: Composite/S-video/component switching and processing
  5. Control Circuit: Microprocessor system with front panel interface
  6. Tuner Circuit: PLL synthesized AM/FM tuner section

CAUTION! High voltage present in power supply section. Exercise extreme caution.

Disassembly Procedures

Adjustment Procedures

Factory adjustment procedures requiring specialized test equipment.

Required Equipment: Audio analyzer, oscilloscope, distortion analyzer, signal generator, dummy loads

DC Offset: Adjust VR801-VR807 for 0mV ±5mV at speaker terminals. Bias Current: Adjust VR851-VR857 for 10mA ±2mA across emitter resistors. Tuner Alignment: FM IF alignment at 10.7MHz, AM IF at 450kHz. Dolby Level: Adjust for 200mV output with Dolby test signal.

Troubleshooting Guide

Systematic troubleshooting procedures for common failure modes.

SymptomPossible CauseCorrective Action
No powerPower supply failureCheck fuse F801, bridge rectifier D801, switching transistor Q801
No audio outputProtection circuit activatedCheck DC offset, shorted outputs, protection relay RL801
Distorted audioBias current incorrectAdjust bias current, check output transistors
No displayFront panel circuitCheck display driver IC, backlight, microprocessor
No digital audioDigital board failureCheck digital input receivers, DSP chip, clock circuits

Parts List

Complete listing of replacement parts with manufacturer part numbers.

  1. Semiconductors: Transistors, ICs, diodes with original part numbers
  2. Passive Components: Resistors, capacitors, inductors with values
  3. Electromechanical: Relays, switches, connectors
  4. Mechanical Parts: Screws, brackets, heat sinks
  5. PC Boards: Main board, power supply, front panel assemblies

Tip: Always use genuine Marantz replacement parts for optimal performance.

PCB Layouts

Printed circuit board layouts showing component placement and trace routing.

Main Board: Double-sided PCB with plated-through holes. Power Supply Board: High-current traces with adequate spacing. Front Panel Board: Single-sided with membrane switch contacts. Tuner Board: Shielded RF section with ground plane.

WARNING! Observe static discharge precautions when handling PC boards.

Schematics

Complete circuit schematics for all major sections.

  1. Power Supply Schematic: AC input to DC output circuits
  2. Amplifier Schematic: 7-channel power amplifier circuits
  3. Audio Processing Schematic: Analog and digital audio paths
  4. Video Switching Schematic: Input selection and output circuits
  5. Control System Schematic: Microprocessor and interface circuits
  6. Tuner Schematic: AM/FM tuner and IF stages

Safety Precautions

Essential safety procedures for service technicians.

Always disconnect AC power before servicing. Discharge large capacitors before testing. Use isolation transformer when testing live circuits. Observe component ratings and replacement specifications. Use appropriate personal protective equipment.

CAUTION! Lethal voltages present. Service by qualified personnel only.

Service Notes

Important service information and common repair procedures.

Service BulletinDescriptionApplication
SB-8500-001Output transistor replacement procedureAll serial numbers
SB-8500-002Power supply capacitor upgradeUnits manufactured before 2004
SB-8500-003DSP firmware update procedureVersion 1.0 to 1.2
SB-8500-004Heat sink mounting torque specificationAll units
SB-8500-005Digital input receiver IC replacementSpecific failure mode

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

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