Marantz 3600 Service Manual

The Marantz 3600 is a high-performance stereo preamplifier featuring advanced circuitry, multiple input/output options, precision tone controls, and professional-grade components. This service manual provides comprehensive technical information for service technicians, including schematics, alignment procedures, troubleshooting guides, and replacement parts lists. Below are key sections covering specifications, block diagrams, circuit descriptions, adjustment procedures, and maintenance guidelines.

1. Technical Specifications 2. Block Diagram Overview 3. Circuit Description 4. Alignment Procedures 5. Test Points & Measurements 6. Component Layout 7. Troubleshooting Guide 8. Replacement Parts List 9. Wiring Diagrams 10. Safety Precautions 11. Service Notes

Technical Specifications

Detailed electrical and mechanical specifications for the Marantz 3600 preamplifier.

Parameter	Specification
Frequency Response	10Hz - 100kHz ±0.5dB
Total Harmonic Distortion	<0.005% at 1kHz
Signal-to-Noise Ratio	>90dB (IHF-A weighted)
Input Sensitivity	2.5mV (MM), 150mV (line)
Input Impedance	47kΩ (phono), 100kΩ (line)
Output Voltage	1V RMS (main out)
Tone Control Range	±10dB at 100Hz and 10kHz
Power Requirements	120V AC, 60Hz, 15W
Dimensions	17" W × 4.5" H × 12" D
Weight	12.5 lbs (5.7 kg)

Block Diagram Overview

System-level functional blocks and signal flow description.

Input Selector: Rotary switch for phono, tuner, aux, tape 1, tape 2
Phono Preamp: RIAA equalized MM/MC stage
Tone Control: Bass, midrange, treble adjustment circuits
Volume/Balance: Dual concentric controls with balance adjustment
Output Buffer: Low impedance driver stage
Power Supply: Regulated ±15V DC rails

NOTE: All signal paths are fully discrete transistor design.

Circuit Description

Detailed analysis of major circuit sections and component functions.

Phono Stage: Dual JFET input with cascode bipolar transistors
Line Stage: Direct-coupled complementary symmetry design
Tone Control: Baxandall-type active equalization
Power Supply: Bridge rectifier with capacitance multiplier
Protection Circuit: DC offset and overcurrent protection

CAUTION! High voltages present - discharge capacitors before servicing.

Alignment Procedures

Step-by-step calibration and adjustment instructions.

DC Offset: Adjust VR101 for 0V ±5mV at main output
Phono Gain: Set VR201 for 40dB gain at 1kHz
RIAA Equalization: Verify response with test records
Tone Control Center: Adjust midrange null at 1kHz
Power Supply: Set ±15.0V DC with VR301/VR302

Test Points & Measurements

Designated test points and expected voltage/current values.

Test Point	Location	Normal Value
TP1	Phono output	100mV RMS (5mV input)
TP2	Line output	1V RMS (150mV input)
TP3	+15V rail	+15.0V ±0.2V
TP4	-15V rail	-15.0V ±0.2V
TP5	Power amp drive	0V DC ±10mV

Component Layout

Physical arrangement of PC boards and major components.

Main Audio Board: Central location with input/output connectors
Power Supply Board: Rear section with transformer and regulators
Front Panel Assembly: Switches, pots, and indicator lights
Rear Panel: RCA jacks, power cord, fuse holder

Tip: Use anti-static precautions when handling PC boards.

Troubleshooting Guide

Common symptoms and diagnostic procedures.

Symptom	Possible Cause	Corrective Action
No output	Power supply failure	Check fuses F101/F102; measure ±15V rails
Distorted sound	DC offset incorrect	Adjust VR101; check output transistors
Hum in phono	Grounding issue	Verify phono ground; check shield connections
Intermittent operation	Oxidized contacts	Clean selector switch; check solder joints
Channel imbalance	Potentiometer wear	Clean/replace volume/balance controls

Replacement Parts List

Critical components and recommended replacements.

Power Transformer: T-1001 (Marantz 3600-001)
Output Transistors: 2SC2240/2SA970 matched pairs
Electrolytic Capacitors: Replace with same values, 105°C rating
Volume Control: Dual 100kΩ audio taper potentiometer
Selector Switch: Rotary 6-position 2-pole

Wiring Diagrams

Interconnection schematics and cable routing.

Main harness: 16-conductor from power supply to audio board
Front panel: 10-conductor to control switches and indicators
Input/output: Shielded audio cables with ground loops
Power: AC mains wiring with proper grounding

WARNING! Observe polarity on electrolytic capacitors.

Safety Precautions

Essential safety procedures for service personnel.

Always disconnect AC power before servicing. Use isolation transformer when testing. Discharge large capacitors. Follow ESD protection procedures. Use specified replacement parts only.

CAUTION! Lethal voltages present - qualified technicians only.

Service Notes

Additional technical information and service tips.

Factory calibration requires audio analyzer. Phono stage particularly sensitive to layout - maintain original component placement. Thermal compound required on regulator transistors. Allow 30 minutes warm-up for precise measurements.

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