Marantz NR1604 Service Manual

The Marantz NR1604 is a slim 7.2-channel AV receiver with 50W per channel, built-in Wi-Fi and Bluetooth, AirPlay compatibility, 4K/3D video pass-through, Audyssey MultEQ auto calibration, multiple HDMI inputs, Ethernet connectivity, and advanced audio processing. Below are key sections for technical specifications, service procedures, troubleshooting, and maintenance guidelines.

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

Technical Specifications

Key technical parameters and electrical characteristics of the NR1604 receiver.

Parameter	Specification
Amplifier Section	7.2 channels, 50W per channel (8Ω, 20Hz-20kHz, 0.08% THD)
Power Supply	AC 120V, 60Hz, 500W maximum power consumption
HDMI	6 inputs (1 front), 1 output, 4K/3D pass-through, ARC support
Network	Built-in Wi-Fi (802.11n), Ethernet, Bluetooth 3.0
Audio Formats	Dolby TrueHD, DTS-HD Master Audio, Dolby Atmos
Dimensions	440 x 105 x 377 mm (W x H x D)
Weight	7.8 kg
Standby Power	0.3W (Network standby: 2.5W)
Frequency Response	10Hz - 100kHz (+1, -3dB)
Signal-to-Noise Ratio	98dB (line), 100dB (phono)

Block Diagram

System architecture and signal flow diagram showing main processing blocks.

Main Power Supply Unit: Switching power supply with multiple voltage rails
Digital Audio Board: HDMI processing, network interface, Bluetooth/Wi-Fi modules
Analog Audio Board: Pre-amplifier stages, phono input, volume control
Power Amplifier Board: 7-channel discrete amplifier section
Front Panel Board: Display, controls, IR receiver
Rear Panel Board: Input/output connectors, antenna terminals

WARNING! High voltages present in power supply section. Disconnect AC power before servicing.

Disassembly Instructions

Step-by-step procedure for accessing internal components.

Remove top cover: Unscrew 6 Phillips screws on top and 2 on rear panel
Remove front panel: Carefully detach plastic clips and disconnect ribbon cables
Access main boards: Remove shield covers and additional mounting screws
Power supply removal: Disconnect all connectors and remove 4 mounting screws
Amplifier board access: Remove heat sink and thermal compound carefully

CAUTION! Use proper ESD protection. Handle circuit boards by edges only.

PCB Layouts

Main Board: Double-sided PCB with ground plane, component side and solder side views
Power Supply Board: High-voltage section clearly marked, transformer locations
Amplifier Board: 7-channel layout with output transistors and protection circuits
Front Panel Board: Display driver IC, button matrix, IR receiver circuit
Digital Board: HDMI receivers, network processor, memory chips

Circuit Diagrams

Complete schematic diagrams for all major circuits.

Power Supply: Switching regulator IC (STR-xxxx), bridge rectifier, filter capacitors, standby circuit. Amplifier Section: Discrete output stages, driver transistors, bias adjustment circuits. Audio Processing: ADC/DAC circuits, DSP processor, analog input stages. HDMI Section: HDMI switcher IC, EDID memory, HDCP circuitry. Network Section: Ethernet PHY, Wi-Fi module, Bluetooth chipset.

Test Points & Measurements

Critical test points and expected voltage/current values.

Power Supply Test Points: +5VSTBY, +12V, +35V, -35V rails
Amplifier Bias Current: Adjust to 15mA per channel using VR501-VR507
DC Offset: Measure at speaker terminals, should be less than ±50mV
HDMI Signal: Check 5V power on HDMI outputs, TMDS signal quality
Clock Signals: Main crystal oscillator 24.576MHz, system clock measurements

Tip: Use calibrated test equipment and follow safety procedures.

Firmware Update Procedures

Methods for updating receiver firmware and recovery procedures.

Network Update: Connect to internet, access setup menu, select firmware update
USB Update: Download firmware to USB drive, insert in front port, follow prompts
Emergency Recovery: Hold STATUS and TUNER PRESET CH + during power-on
Factory Reset: Initialize all settings after firmware update
Version Check: Verify successful update in system information menu

WARNING! Do not interrupt power during firmware update. May cause permanent damage.

Troubleshooting Flowcharts

Systematic diagnostic procedures for common issues.

Symptom	Diagnostic Steps	Probable Cause
No Power	Check AC input, fuse, standby voltage, power supply IC	Blown fuse, faulty power IC, short circuit
No Sound	Verify input selection, check amplifier voltages, test protection circuit	Amplifier failure, protection trigger, mute circuit
HDMI Issues	Test HDMI output voltage, check EDID, verify source compatibility	HDMI board failure, HDCP error, cable issues
Network Problems	Check Ethernet connection, Wi-Fi module, network settings	Network chip failure, antenna connection, firmware
Overheating	Monitor temperature, check fan operation, verify bias current	Clogged vents, failed fan, excessive bias

Parts List & Replacement

Critical replacement components and part numbers.

Main ICs: DSP Processor (DSP-xxxx), HDMI Switcher (Mxxxx), Power Supply IC (STR-xxxx). Transistors: Output pairs (2SCxxxx/2SAxxxx), driver transistors. Capacitors: Main filter capacitors (10000μF/63V), SMPS capacitors. Fuses: Main fuse (T6.3A/250V), secondary fuses. Connectors: HDMI ports, speaker terminals, RCA jacks.

Safety Precautions

Essential safety procedures for service technicians.

CAUTION! Always disconnect AC power before servicing. Use isolation transformer for live measurements. Discharge large capacitors before handling. Follow ESD protection procedures. Use proper tools and test equipment.

Service Notes

Important service information and special procedures.

Warranty: 3-year limited warranty from date of purchase
Service Centers: Authorized Marantz service centers only
Calibration: Use Audyssey setup microphone for proper calibration
Software Tools: Special service software required for advanced diagnostics
Documentation: Keep detailed service records for warranty claims

Support: 1-800-432-3088; www.marantz.com