Marantz PM15S2 Service Manual

The Marantz PM15S2 is a high-performance integrated stereo amplifier featuring advanced HDAM (Hyper Dynamic Amplifier Module) technology, dual monaural construction, high-current power supply, toroidal transformer, gold-plated connectors, and comprehensive input/output options. Below are key sections for technical specifications, circuit diagrams, adjustment procedures, troubleshooting, and maintenance guidelines.

1. Technical Specifications 2. Block Diagrams 3. Circuit Descriptions 4. Adjustment Procedures 5. Test Points & Measurements 6. Parts List 7. PCB Layouts 8. Troubleshooting Guide 9. Maintenance Procedures 10. Safety Precautions 11. Service Notes

Technical Specifications

Key electrical and mechanical specifications for the PM15S2 amplifier.

Parameter	Specification
Power Output	2 x 85W (8Ω), 2 x 140W (4Ω)
Frequency Response	5Hz - 100kHz (+0/-3dB)
Total Harmonic Distortion	<0.005% (20Hz-20kHz)
Input Sensitivity	200mV (LINE), 2.5mV (PHONO MM)
Signal-to-Noise Ratio	100dB (LINE), 87dB (PHONO)
Input Impedance	47kΩ (LINE), 47kΩ/100pF (PHONO)
Power Supply	AC 120V/230V, 50/60Hz
Power Consumption	280W (maximum)
Dimensions	440 x 156 x 428mm (W x H x D)
Weight	18.5kg

Block Diagrams

System block diagrams showing signal flow and power distribution.

Main System Block Diagram: Shows overall signal path from inputs to outputs.
Power Supply Block Diagram: Illustrates transformer, rectification, and regulation stages.
Amplifier Section: Details preamp and power amplifier stages.
Control System: Microprocessor control and relay switching circuits.

NOTE! Refer to actual service manual for detailed schematic diagrams.

Circuit Descriptions

Detailed explanations of major circuit sections.

Power Supply Circuit: Toroidal transformer with dual secondary windings.
HDAM Circuits: Current-mirror loaded differential amplifier stages.
Phono Equalizer: RIAA equalization with low-noise transistors.
Protection Circuit: DC detection, thermal protection, and relay delay.
Volume Control: Motorized ALPS potentiometer with remote control.

CAUTION! High voltages present in power supply section.

Adjustment Procedures

DC Offset Adjustment: Adjust VR801/VR802 for 0mV ±5mV at speaker terminals.
Bias Current Adjustment: Set VR803/VR804 for 10mV across emitter resistors.
Phono Equalization: Verify RIAA curve accuracy with test equipment.
Protection Circuit: Test DC detection and thermal shutdown functions.
Input Level Matching: Balance input sensitivities for consistent volume.

Test Points & Measurements

Critical test points and measurement procedures.

Test Point	Location	Normal Value
TP1 (+B)	Power Supply Board	+45V DC
TP2 (-B)	Power Supply Board	-45V DC
TP3 (+15V)	Control Board	+15V DC
TP4 (-15V)	Control Board	-15V DC
TP5 (DC Offset)	Amplifier Board	0mV ±5mV
TP6 (Bias)	Amplifier Board	10mV ±2mV

Parts List

Critical replacement components and part numbers.

Power Transistors: 2SC5200/2SA1943 matched pairs
Toroidal Transformer: T-1001 (primary: 0-100-120V)
Main Filter Capacitors: 15,000μF/63V x 2
Output Relays: MY4-02-DC24
Volume Potentiometer: RK-50112A00
HDAM Modules: SM-25A01 (preamp), SM-25A02 (driver)

WARNING! Use only genuine Marantz replacement parts.

PCB Layouts

Printed circuit board layouts and component locations.

Main Amplifier Board: Component side and solder side views.
Power Supply Board: Transformer connections and rectifier layout.
Control Board: Microprocessor and relay driver circuits.
Input Selector Board: Source switching and phono stage.

Tip: Use high-resolution diagrams for accurate component identification.

Troubleshooting Guide

Common problems and diagnostic procedures.

Symptom	Possible Cause	Corrective Action
No power	Fuse blown, transformer fault	Check F801/F802; measure primary voltage
No sound output	Protection circuit, relay failure	Check relay drive voltage; test output transistors
Distorted sound	Bias current incorrect, damaged transistors	Adjust bias; check output devices
Hum/buzz	Ground loop, filter capacitor failure	Check ground connections; test main capacitors
Intermittent operation	Cold solder joints, connector issues	Resolder joints; clean and reseat connectors

Maintenance Procedures

Routine maintenance and cleaning guidelines.

Internal Cleaning: Use compressed air to remove dust from heatsinks and boards.
Contact Cleaning: Clean input/output connectors with contact cleaner.
Potentiometer Maintenance: Clean volume and selector controls.
Thermal Compound: Reapply thermal paste on power transistors if necessary.

CAUTION! Disconnect power and discharge capacitors before maintenance.

Safety Precautions

Essential safety information for service personnel.

Always disconnect AC power before servicing.
Discharge large capacitors before working on power supply.
Use isolation transformer when testing live circuits.
Replace safety-critical components with exact specifications.
Verify proper grounding and insulation after repairs.

Service Notes

Important service information and updates.

Service Bulletin SB-025: Updated bias adjustment procedure for improved thermal stability. Service Note SN-118: Revised output transistor matching specifications. Warranty information: 3 years parts and labor. For technical support, contact Marantz Service Department at 1-800-654-0523 or [email protected]. Latest service manuals available at www.marantz.com/service.

Reset: Power cycle to clear protection lockouts.

Calibration: Requires oscilloscope and audio test equipment.