Marantz PM7001 Service Manual

The Marantz PM7001 is a high-performance integrated stereo amplifier featuring 70W per channel (8Ω), high-current power supply, discrete power amplifier configuration, Marantz HDAM modules, gold-plated input terminals, direct mode for pure audio signal path, tone controls, source direct switching, and comprehensive protection circuits. This service manual covers technical specifications, circuit diagrams, adjustment procedures, troubleshooting, and maintenance guidelines for qualified service technicians.

1. Technical Specifications 2. Block Diagram 3. Circuit Description 4. Adjustment Procedures 5. Disassembly Instructions 6. PCB Layouts 7. Schematic Diagrams 8. Parts List 9. Troubleshooting Guide 10. Safety Precautions 11. Service Notes

Technical Specifications

Complete electrical and mechanical specifications for the PM7001 integrated amplifier.

Parameter	Specification
Power Output	70W + 70W (8Ω, 20Hz-20kHz, 0.08% THD)
Total Harmonic Distortion	0.08% (20Hz-20kHz at 70W, 8Ω)
Frequency Response	5Hz-50kHz (+1/-3dB)
Input Sensitivity	200mV (MM Phono), 2.5V (Line)
Signal-to-Noise Ratio	100dB (Line), 87dB (Phono MM)
Damping Factor	100 (8Ω, 1kHz)
Power Consumption	230W (maximum), 65W (no signal)
Dimensions	440 x 385 x 125mm (W x D x H)
Weight	9.8kg
Power Supply	AC 120V/230V, 50/60Hz

Block Diagram

System block diagram showing signal flow and major functional blocks.

Input Selector: CD, Tuner, Phono, Line 1-3, Tape
Phono Equalizer: RIAA equalization for MM cartridges
Tone Control: Bass, Treble, Balance controls
Volume Control: Motorized ALPS potentiometer
Power Amplifier: Discrete symmetrical configuration
Power Supply: Toroidal transformer with regulated supplies
Protection Circuit: DC detection, thermal protection

WARNING! High voltages present - qualified personnel only.

Circuit Description

Detailed circuit analysis of major sections.

Power Supply: Toroidal transformer, bridge rectifier, smoothing capacitors
Input Stage: HDAM (Hyper Dynamic Amplifier Module) buffer
Voltage Amplifier: Complementary differential pairs
Driver Stage: Current amplification for output devices
Output Stage: Complementary triple Darlington configuration
Protection: Relay-based speaker protection with DC detection

CAUTION! Always discharge power supply capacitors before servicing.

Adjustment Procedures

DC Offset: Adjust VR701/VR702 for 0mV ±5mV at speaker terminals
Bias Current: Set VR703/VR704 for 10mV across emitter resistors
Phono Equalization: Verify RIAA response with test equipment
Protection Circuit: Test DC detection and relay timing
Power Supply: Measure ±45V rails under load conditions
Input Sensitivity: Calibrate for specified input levels

Disassembly Instructions

Step-by-step disassembly procedure for service access.

Front Panel: Remove knobs, unscrew front panel assembly.

Remove top cover: 6 screws on rear and sides
Remove bottom plate: 4 screws for component access
Front panel removal: Disconnect ribbon cables carefully
Main board access: Remove mounting screws and standoffs
Heat sink removal: Required for output transistor replacement

Tip: Document cable positions and take photos during disassembly.

PCB Layouts

Printed circuit board layouts for main board, power supply, and front panel.

Main Amplifier Board: Component placement and trace routing
Power Supply Board: Transformer connections and rectification
Front Panel Board: Switch and display circuitry
Input Selector Board: Source switching relays and routing

WARNING! Observe electrostatic discharge precautions when handling PCBs.

Schematic Diagrams

Complete schematic diagrams for all circuit sections.

Power Amplifier Section: Input to output stage
Power Supply: Primary and secondary circuits
Phono Stage: RIAA equalization circuit
Tone Control: Bass, treble, and balance circuits
Protection Circuit: DC detection and relay driver
Input Selector: Source switching matrix

WARNING! Schematics show live AC voltages - extreme caution required.

Parts List

Complete component listing with manufacturer part numbers.

Reference	Description	Part Number
Q701-Q704	Output Transistor 2SC5200/2SA1943	MAR-5200-1943
IC701, IC702	HDAM Module	MAR-HDAM-PM7
T701	Toroidal Transformer	MAR-TRF-7001
RY701	Speaker Protection Relay	OMRON G2R-1
C701, C702	Main Filter Capacitor 10000μF/63V	MAR-CAP-10000
VR701-VR704	Adjustment Potentiometer	MAR-VR-1K

Troubleshooting Guide

Symptom	Possible Cause	Corrective Action
No power	Fuse, power switch, transformer	Check F701/F702; measure primary voltage
Protection relay not engaging	DC offset, protection circuit fault	Measure output DC; check Q751-Q754
Distorted audio	Bias current, output transistors	Adjust bias; check Q701-Q704
Hum/buzz	Grounding, filter capacitors	Check C701/C702; verify ground connections
One channel dead	Amplifier stage, input selector	Signal trace from input to output

Test Points: TP701 (Bias), TP702 (DC Offset), TP703 (+45V), TP704 (-45V)

Safety Precautions

Essential safety procedures for service personnel.

CAUTION! Lethal voltages present - use isolation transformer and follow safety protocols.

Service Notes

Factory service bulletins and common repair procedures.

Marantz Service Division: Contact for technical support and genuine parts. Copyright © 2006 Marantz America, Inc. All service should be performed by qualified technicians only. For service support, contact authorized Marantz service centers or visit www.marantz.com.