The Marantz SR6400 is a high-performance AV receiver featuring Dolby Digital and DTS decoding, 6-channel amplification (100W x 6), multiple audio/video inputs, digital optical/coaxial inputs, AM/FM tuner, preamp outputs, speaker A/B switching, and advanced surround sound processing. This service manual provides technical specifications, circuit diagrams, troubleshooting procedures, and repair guidelines for qualified service technicians.
Detailed electrical and mechanical specifications for the Marantz SR6400 AV receiver.
| Parameter | Specification |
|---|---|
| Power Output | 100W x 6 (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 (line input) |
| Input Sensitivity | 200mV (line), 2.5mV (phono) |
| Digital Inputs | Optical x2, Coaxial x2 |
| Video Inputs | Composite x4, S-Video x3, Component x2 |
| Audio Inputs | Line x6, Phono, Tape |
| Dimensions | 440 x 161 x 418mm (W x H x D) |
| Weight | 12.5kg |
System block diagrams showing signal flow and major functional blocks.
WARNING! These diagrams are for qualified technicians only. Do not attempt repairs without proper training.
Detailed explanations of major circuit sections and their operation.
CAUTION! High voltages present in power supply section. Disconnect power before servicing.
Factory adjustment procedures requiring specialized test equipment.
Required Equipment: Audio analyzer, oscilloscope, distortion meter, dummy loads
DC Offset: Adjust VR601-VR606 for 0mV ±5mV at speaker terminals
Bias Current: Adjust VR701-VR706 for 10mA ±2mA
Tuner Alignment: FM/AM IF and oscillator adjustments
DSP Calibration: Digital processor alignment via service mode
Systematic troubleshooting procedures for common failures.
| Symptom | Possible Cause | Corrective Action |
|---|---|---|
| No power | Fuse, power supply | Check F601, measure +5VSTBY, replace power supply IC |
| No audio output | Protection circuit, amplifier | Check protection relay, measure amplifier outputs |
| Distorted sound | Bias current, damaged outputs | Adjust bias, replace output transistors |
| No display | Display driver, microcontroller | Check VFD voltage, replace display driver IC |
| Tuner not working | Tuner unit, power supply | Check tuner B+ voltage, replace tuner assembly |
Complete listing of components with manufacturer part numbers.
| Part Number | Description | Qty |
|---|---|---|
| 2SC5200 | Power transistor NPN | 12 |
| 2SA1943 | Power transistor PNP | 12 |
| STR-6656 | Switching regulator IC | 1 |
| NJM4580 | Dual op-amp | 8 |
| LA1266 | FM/AM tuner IC | 1 |
Printed circuit board layouts for all major assemblies.
Tip: Use magnifying glass for component identification.
Complete circuit schematics for all sections.
WARNING! Schematics contain high-voltage sections. Exercise extreme caution.
Essential safety procedures for service technicians.
Always disconnect AC power before servicing. Discharge large capacitors. Use isolation transformer when testing live circuits. Wear safety glasses. Follow ESD precautions when handling semiconductors.
CAUTION! Lethal voltages present. Only qualified personnel should perform repairs.
Important service information and common repair issues.
Common failures: Power supply IC STR-6656, output transistors 2SC5200/2SA1943, protection relay. Service mode access: Press TONE and STATUS while powering on. Factory reset procedure available in service mode. Calibration requires specific test equipment.
Service Contacts: Marantz Service Department: 1-800-654-6633
Website: www.marantz.com