Marantz SR 5100 Service Manual

The Marantz SR 5100 is a high-performance audio/video receiver featuring Dolby Digital and DTS decoding, 5.1 channel surround sound, 100W per channel power output, multiple audio/video inputs, digital optical and coaxial inputs, AM/FM tuner, speaker setup calibration, and advanced audio processing. This service manual provides technical specifications, circuit diagrams, troubleshooting guides, and repair procedures for qualified service technicians.

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

Technical Specifications

Detailed technical specifications and performance characteristics of the Marantz SR 5100 receiver.

Parameter	Specification
Power Output	100W per channel (8Ω, 20Hz-20kHz, 0.08% THD)
Frequency Response	10Hz-100kHz (+1/-3dB)
Total Harmonic Distortion	0.08% (20Hz-20kHz at rated power)
Signal-to-Noise Ratio	100dB (IHF-A)
Input Sensitivity	200mV (line inputs)
Surround Formats	Dolby Digital, DTS, Dolby Pro Logic
Video Inputs	3 composite, 2 S-Video
Audio Inputs	6 analog, 2 digital optical, 1 coaxial
Tuner Section	AM/FM with 30 station presets
Power Consumption	450W maximum

Block Diagrams

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

Main System Block Diagram: Overview of entire receiver architecture
Audio Processing Block: Digital signal processing path
Power Supply Block: AC to DC conversion and regulation
Amplifier Section: Power amplifier stages and protection circuits
Tuner Block: AM/FM reception and processing

WARNING! High voltages present in power supply and amplifier sections. Exercise extreme caution when servicing.

Circuit Descriptions

Detailed explanations of major circuit sections and their operation.

Power Supply Circuit: Switching power supply with multiple voltage rails
Main Amplifier Circuit: Discrete power amplifier design with protection
Digital Audio Processor: 24-bit/96kHz processing core
Video Switching Circuit: Composite and S-Video matrix switching
Microcontroller System: System control and user interface

CAUTION! Static-sensitive components present. Use proper ESD precautions.

Disassembly Procedures

Top Cover Removal: Remove 6 screws from rear panel and sides
Front Panel Removal: Disconnect ribbon cables and remove 4 screws
Main Board Access: Remove shield and disconnect all connectors
Power Supply Board: Discharge capacitors before servicing
Amplifier Heat Sink: Thermal compound replacement procedure
Tuner Module: Special alignment tools required
Rear Panel Connectors: Desoldering techniques for replacement

Test Points & Measurements

Critical test points and recommended measurement procedures for proper diagnosis.

Power Supply: TP1 (+12V), TP2 (+5V), TP3 (+3.3V), TP4 (-12V)

Amplifier Section: DC offset (should be <50mV), bias current (25mA per channel)

Audio Processing: Digital signal levels, clock frequencies (11.2896MHz, 16.9344MHz)

Protection Circuits: Over-current detection, thermal protection thresholds

Adjustment Procedures

Factory adjustment procedures for optimal performance.

DC Offset Adjustment: VR101-VR105 for each channel
Bias Current Adjustment: VR201-VR205 (25mA setting)
Dolby Level Calibration: Using test tones and reference levels
Tuner Alignment: FM oscillator and RF stages
Display Contrast: Internal potentiometer for front panel

Tip: Use specified test equipment and follow procedures exactly.

Troubleshooting Flowcharts

Step-by-step diagnostic procedures for common failure modes.

No Power: Check AC input, fuse F001, standby power supply
No Audio Output: Verify protection circuit status, amplifier stages
Distorted Sound: Check bias current, DC offset, power supply ripple
No Display: Front panel power, microcontroller reset circuit
Tuner Problems: Antenna input, tuner module power, I2C bus
Digital Input Issues: Signal presence detection, format recognition

WARNING! Always disconnect AC power before replacing components.

Parts List

Complete listing of components with manufacturer part numbers.

Part Number	Description	Qty
IC501	Digital Audio Processor	1
Q701-Q705	Output Transistors 2SC5200/2SA1943	10
C801	Main Filter Capacitor 10000μF/63V	2
F001	Main Fuse 5A/250V	1
TR001	Power Transformer	1
IC301	Microcontroller	1
D101-D104	Rectifier Diodes	4

PCB Layouts

Printed circuit board layouts for all major assemblies.

Main Board: 6-layer design with ground planes

Power Supply Board: High-current traces and thermal management

Front Panel Board: Display and control interface

CAUTION! Observe proper soldering techniques to avoid board damage.

Schematics

Complete schematic diagrams for all circuit sections.

Main System Schematic: Overall system interconnections
Power Supply Schematic: AC input to DC output stages
Amplifier Schematic: Input to output stage with protection
Audio Processing: Digital and analog signal paths
Control System: Microcontroller and peripheral circuits
Tuner Circuit: AM/FM reception and processing

Service Notes

Issue	Solution	Notes
Protection mode	Check output transistors	Replace in complementary pairs
No digital audio	Verify input selection	Check optical receiver module
Display dim	Adjust contrast pot	Located on front panel board
Hum in audio	Check ground connections	Verify star grounding
Remote issues	Test IR receiver	Check 5V supply to module

Factory Reset: Hold TUNER PRESET and press POWER (front panel)

Service Support: Contact authorized Marantz service centers only