Marantz PM66SE Service Manual

The Marantz PM66SE is a high-quality integrated stereo amplifier featuring advanced circuitry, dual mono construction, gold-plated connectors, and high-current power supply. This service manual provides comprehensive technical information for service technicians, including schematics, alignment procedures, troubleshooting guides, and replacement parts lists for proper maintenance and repair of the PM66SE amplifier.

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

Technical Specifications

Complete electrical and mechanical specifications for the Marantz PM66SE integrated amplifier.

Parameter	Specification
Power Output	60W + 60W (8Ω, 20Hz-20kHz)
Total Harmonic Distortion	<0.008% (1kHz, 50W)
Frequency Response	5Hz - 50kHz (+0/-3dB)
Input Sensitivity	150mV (LINE), 2.5mV (PHONO)
Signal-to-Noise Ratio	96dB (LINE), 80dB (PHONO)
Input Impedance	47kΩ (LINE), 47kΩ/100pF (PHONO)
Damping Factor	>100 (8Ω, 1kHz)
Power Consumption	220W (max)
Dimensions	440 x 125 x 345mm (W x H x D)
Weight	8.5kg

Block Diagram & Circuit Overview

System block diagram showing signal flow and major circuit blocks.

Input Selector Circuit: Relay-based input switching
Phono Equalizer: RIAA equalization with low-noise transistors
Tone Control: Bass and treble controls with defeat switch
Volume Control: ALPS motorized potentiometer
Power Amplifier: Complementary symmetry output stage
Power Supply: Toroidal transformer with dual rectifiers
Protection Circuit: DC detection and relay delay

WARNING! High voltages present in power supply section. Discharge capacitors before servicing.

Disassembly Instructions

Step-by-step disassembly procedure for accessing internal components.

Remove top cover: Unscrew 6 Phillips screws on top panel
Remove front panel: Detach 4 screws and carefully disconnect control knobs
Access main PCB: Remove 8 mounting screws securing main board
Remove power supply: Disconnect all wiring and remove 4 transformer mounting screws
Access rear panel connectors: Remove RCA and speaker terminal blocks

CAUTION! Handle PCBs carefully to avoid damaging traces and components.

PCB Layouts

Main Amplifier Board: Component placement and trace routing
Power Supply Board: Rectifier and filter capacitor layout
Input Selector Board: Relay and switching circuitry
Front Panel Board: Control switches and indicators
Phono Board: RIAA equalization components

Schematic Diagrams

Complete schematic diagrams for all circuit sections.

Main Sections: Power amplifier, preamplifier, tone control, phono stage, power supply, protection circuit, input selector.

All schematics include component values, transistor types, IC part numbers, and test point locations. Reference designators match PCB layouts for easy cross-reference.

Alignment & Adjustment Procedures

Factory adjustment procedures for optimal performance.

DC Offset Adjustment: VR601, VR602 - adjust for 0mV ±5mV at speaker terminals
Bias Current Adjustment: VR603, VR604 - set for 15mA across emitter resistors
Phono Equalization: Verify RIAA response with test equipment
Input Level Matching: Adjust input sensitivity for uniform volume levels

Tip: Use calibrated test equipment and allow 30 minutes warm-up before adjustments.

Voltage Measurements

Reference voltage measurements at key test points.

Test Point	Voltage (DC)	Notes
TP1 (+B)	+45V ±2V	Positive rail voltage
TP2 (-B)	-45V ±2V	Negative rail voltage
TP3 (+15V)	+15V ±0.5V	Preamp positive supply
TP4 (-15V)	-15V ±0.5V	Preamp negative supply
TP5 (Speaker Out)	0mV ±5mV	DC offset measurement

Parts List & Replacement Guide

Complete component listing with manufacturer part numbers.

Transistors: 2SC2240, 2SA970, 2SC2705, 2SA1145, 2SD669, 2SB649
Integrated Circuits: NJM4558, NJM2068, TA7317P
Electrolytic Capacitors: Specify voltage and temperature ratings
Resistors: 1/4W metal film, 1% tolerance preferred
Potentiometers: ALPS motorized volume, tone controls
Relays: MY4 DC24V for speaker protection

WARNING! Use only specified replacement parts to maintain performance and safety.

Troubleshooting Flowcharts

Systematic troubleshooting guides for common problems.

Symptom	Possible Cause	Corrective Action
No sound output	Protection relay, blown fuses	Check speaker relay, measure rail voltages, verify protection circuit
Distorted audio	Bias current, output transistors	Adjust bias current, check output transistors for shorts
Hum or noise	Grounding, capacitors	Check ground connections, replace filter capacitors
One channel dead	Input selector, amplifier stage	Trace signal path, check input relays, measure stage voltages
Overheating	Bias current, ventilation	Verify bias setting, ensure proper ventilation

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 when handling semiconductors.

CAUTION! Lethal voltages present. Only qualified technicians should perform internal repairs.

Service Notes

Additional technical information and service tips.

Factory service bulletins and updates
Common failure modes and solutions
Modification procedures (if applicable)
Calibration equipment requirements
Warranty service procedures

Service Support: Contact authorized Marantz service centers for genuine parts and technical support.