Marantz SR 2000 Service Manual

The Marantz SR 2000 is a high-performance stereo receiver featuring advanced audio processing, multiple input/output options, and professional-grade amplification. This service manual provides comprehensive technical documentation for service technicians, including schematics, alignment procedures, troubleshooting guides, and replacement part information for proper maintenance and repair.

1. Technical Specifications 2. Block Diagrams 3. Circuit Descriptions 4. Alignment Procedures 5. Disassembly Instructions 6. Test Points & Measurements 7. Replacement Parts List 8. Schematic Diagrams 9. Troubleshooting Flowcharts 10. Safety Precautions 11. Service Notes

Technical Specifications

Complete technical specifications and performance characteristics of the Marantz SR 2000 stereo receiver.

Parameter	Specification
Power Output	100W per channel (8Ω, 20Hz-20kHz)
Total Harmonic Distortion	<0.05% at rated output
Frequency Response	10Hz-100kHz (+0/-3dB)
Signal-to-Noise Ratio	>100dB (IHF-A)
Input Sensitivity	Phono: 2.5mV, Line: 150mV
Input Impedance	Phono: 47kΩ, Line: 50kΩ
Damping Factor	>100 at 8Ω
Tone Controls	Bass: ±10dB at 100Hz, Treble: ±10dB at 10kHz
Power Requirements	120V AC, 60Hz, 450W max
Dimensions	17.1" W × 5.9" H × 15.4" D

Block Diagrams

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

Main System Block Diagram: Overview of entire receiver architecture
Preamplifier Section: Input switching and tone control circuits
Power Amplifier Section: Output stage and protection circuits
Power Supply Section: Voltage regulation and distribution
Tuner Section: RF/IF processing and demodulation

NOTE: Refer to schematic diagrams for detailed component-level information.

Circuit Descriptions

Detailed descriptions of major circuit sections and their operational principles.

Preamplifier Circuit: High-impedance JFET input stage with low-noise op-amps
Phono Equalizer: RIAA-compliant equalization with precision components
Tone Control: Baxandall-type bass and treble controls
Power Amplifier: Complementary symmetry output stage with thermal protection
Protection Circuit: DC detection, over-current, and thermal shutdown
Power Supply: Toroidal transformer with regulated ± supplies

Alignment Procedures

Step-by-step alignment and calibration procedures for optimal performance.

DC Offset Adjustment: Adjust VR501/502 for 0mV ±5mV at speaker terminals
Bias Current Adjustment: Set VR503/504 for 20mA across emitter resistors
Phono Equalization: Verify RIAA response using test records
FM Tuner Alignment: Adjust RF, IF, and detector stages per alignment chart
Dolby Circuit Adjustment: Calibrate Dolby levels using reference tones

WARNING! Use calibrated test equipment and follow safety procedures.

Disassembly Instructions

Proper disassembly sequence to access internal components for service.

Remove top cover: Remove 6 Phillips screws from rear and sides
Remove front panel: Detach knobs and remove 4 front panel screws
Access main board: Remove shield covers and connector restraints
Remove tuner assembly: Detach RF connections and mounting hardware
Power supply access: Discharge capacitors before handling

CAUTION! Always disconnect power and discharge capacitors before servicing.

Test Points & Measurements

Critical test points and expected voltage/current measurements for diagnostics.

Test Point	Location	Normal Value
TP1 (+B)	Power supply output	+45V DC ±2V
TP2 (-B)	Power supply output	-45V DC ±2V
TP3 (+15V)	Regulator output	+15V DC ±0.5V
TP4 (-15V)	Regulator output	-15V DC ±0.5V
TP5 (Bias)	Output stage	20mA ±2mA
TP6 (Offset)	Speaker output	0mV ±5mV

Replacement Parts List

Authorized replacement components with manufacturer part numbers.

Output Transistors: 2SC3281 / 2SA1302 (Sanken)
Driver Transistors: 2SC2705 / 2SA1145 (Toshiba)
Power Supply Rectifiers: 1N5408 (3A, 1000V)
Main Filter Capacitors: 10,000μF/63V (Nichicon)
Op-amps: NJM4558 (JRC)
Fuses: 4A SB (slow-blow)
LEDs: Standard 5mm red/green

Schematic Diagrams

Complete schematic diagrams for all circuit sections at component level.

Main Amplifier Schematic: Complete power amplifier circuit
Preamplifier Schematic: Input switching and tone control circuits
Power Supply Schematic: Transformer, rectification, and regulation
Protection Circuit: Speaker protection and thermal management
Tuner Section: FM/AM tuner circuitry
Control Logic: Function switching and indicator circuits

NOTE: Schematics show component values, test points, and waveform references.

Troubleshooting Flowcharts

Systematic diagnostic flowcharts for common service issues.

Symptom	Diagnostic Procedure	Common Causes
No power	Check AC input, fuses, power switch	Blown fuse, faulty switch, transformer
No audio output	Verify protection circuit, check DC offset	Output transistors, bias circuit
Distorted sound	Check bias current, test output stage	Bias misadjustment, failed drivers
Hum/buzz	Check grounding, filter capacitors	Failed capacitors, ground loops
Intermittent operation	Inspect solder joints, connectors	Cold solder joints, worn connectors

Safety Precautions

Essential safety procedures for service technicians.

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

WARNING! Lethal voltages present. Only qualified technicians should perform service.

Service Notes

Important service tips and manufacturer updates.

Use only specified replacement parts to maintain performance
Apply thermal compound when replacing output transistors
Check all solder joints on power components during repair
Verify proper heatsink mounting torque (0.5-0.6 N·m)
Update service bulletins available from Marantz technical support

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