Marantz SR 7200 Service Manual

The Marantz SR 7200 is a high-performance AV receiver featuring Dolby Digital and DTS decoding, 7-channel amplification, multiple audio/video inputs, digital audio inputs, AM/FM tuner, and advanced surround sound processing. This service manual provides technical information for qualified service technicians including schematics, alignment procedures, troubleshooting guides, and replacement parts information.

Technical Specifications

Detailed technical specifications and performance characteristics of the Marantz SR 7200 AV receiver.

Parameter	Specification
Power Output	100W x 7 channels (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), 2.5mV (MM phono)
Digital Inputs	Coaxial x 2, Optical x 2
Video Inputs	Composite x 4, S-Video x 3, Component x 2
Audio Inputs	7.1 channel, Phono, CD, Tape, etc.
Surround Formats	Dolby Digital, DTS, Dolby Pro Logic II
Power Consumption	650W maximum

Block Diagrams

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

1. Main System Block Diagram: Overview of entire receiver architecture
2. Audio Processing Block: DSP and decoding circuitry
3. Power Amplifier Block: 7-channel amplifier section
4. Power Supply Block: Main and auxiliary power supplies
5. Tuner Block: AM/FM receiver circuitry
6. Video Processing Block: Video switching and processing

WARNING! For qualified service personnel only. High voltages present in power supply and amplifier sections.

Circuit Descriptions

Detailed descriptions of major circuit sections and their operation.

1. Power Supply Circuit: Switching power supply with multiple voltage rails
2. Digital Audio Processor: 24-bit/192kHz DAC and DSP processing
3. Amplifier Circuit: Discrete 7-channel power amplifier design
4. Protection Circuit: DC detection, thermal protection, and overload protection
5. Microprocessor Control: Main system control and user interface
6. Tuner Circuit: PLL synthesized AM/FM tuner with RDS

CAUTION! Always discharge large capacitors before servicing power supply section.

Disassembly Procedures

• Top Cover Removal: Remove 6 screws from rear panel and 2 from sides
• Front Panel Removal: Disconnect ribbon cables and remove 4 screws
• Main Board Access: Remove shield and disconnect all connectors
• Power Supply Removal: Discharge capacitors and remove mounting screws
• Amplifier Module: Remove heat sink and output transistors carefully
• Tuner Module: Remove shielding and disconnect antenna inputs

Alignment and Adjustment

Factory alignment procedures and test point locations for proper calibration.

DC Offset Adjustment: Adjust VR601-VR607 for 0mV ±5mV at speaker terminals

Bias Current Adjustment: Set VR651-VR657 for 10mA across emitter resistors

Tuner Alignment: FM IF alignment at TP1, AM antenna trimmer adjustment

DSP Processor: No user adjustment required - factory programmed

Video Level: Adjust for 1Vp-p composite video output

Troubleshooting Flowcharts

Systematic troubleshooting procedures for common failure modes.

Symptom	Test Procedure	Likely Cause
No power	Check AC input, fuse F001, standby voltage	Power supply failure, blown fuse
Protection mode	Check DC offset, output transistors	Shortened outputs, failed drivers
No audio	Signal trace from inputs to outputs	Failed processor, mute circuit
Distorted sound	Check bias current, power supply voltages	Bias misadjustment, failed capacitors
No video	Check video IC power, input/output signals	Failed video switch IC

Schematic Diagrams

Complete schematic diagrams for all circuit boards and modules.

1. Main System Schematic: Microprocessor and control circuits
2. Power Supply Schematic: Switching regulator and voltage rails
3. Amplifier Schematic: 7-channel power amplifier circuits
4. Audio Processor Schematic: DAC and DSP circuitry
5. Tuner Schematic: AM/FM tuner and RDS decoder
6. Video Circuit Schematic: Video switching and processing

Tip: Use high-impedance multimeter for voltage measurements in digital circuits.

Parts List

Complete listing of all components with manufacturer part numbers.

Reference	Description	Part Number
Q601-Q607	Output Transistor 2SC5200	2SC5200-O(T)
Q651-Q657	Output Transistor 2SA1943	2SA1943-O(T)
IC601	Digital Audio Processor	MN67740MH
IC701	System Microprocessor	HD6437043F20
F001	Main Fuse	5A 250V T-type
C801	Main Filter Capacitor	10000μF 63V
TR001	Power Transformer	EI-76-28

PCB Layouts

Printed circuit board layouts showing component placement and trace routing.

Main Board: Double-sided PCB with ground plane

Power Supply Board: High-current traces with adequate spacing

Amplifier Board: Thermal management considerations

Front Panel Board: User interface and display components

WARNING! Observe proper ESD precautions when handling circuit boards.

Service Precautions

Important safety information and service guidelines for technicians.

Always disconnect AC power before servicing. Use isolation transformer when testing live circuits. Observe component orientation when replacing parts. Use specified replacement parts only. Check for proper insulation and clearance after repairs.

CAUTION! Lethal voltages present in power supply section. Use extreme caution.

Test Points and Voltages

Reference voltages and test point locations for verification and diagnosis.

Test Point	Normal Voltage	Description
TP+12V	+12V ±5%	Digital circuit supply
TP+5V	+5V ±2%	Microprocessor supply
TP-12V	-12V ±5%	Negative rail
TP+35V	+35V ±5%	Amplifier positive rail
TP-35V	-35V ±5%	Amplifier negative rail
TP STBY	+5V	Standby power

Reset: Power cycle to reset microprocessor if unit locks up.

Service Support: Contact Marantz technical support for additional assistance.