Marantz 5025 Service Manual

The Marantz 5025 is a professional-grade stereo receiver featuring advanced audio processing, multiple input/output options, and robust construction for reliable performance. This service manual provides comprehensive technical information for installation, operation, maintenance, and troubleshooting of the Marantz 5025 audio system. Below are key sections covering specifications, installation procedures, operational controls, maintenance guidelines, and technical service information.

Technical Specifications

Complete technical specifications and performance characteristics of the Marantz 5025 stereo receiver.

Parameter	Specification
Power Output	50W RMS per channel (8Ω)
Frequency Response	20Hz - 20kHz (±0.5dB)
Total Harmonic Distortion	<0.05% at rated power
Signal-to-Noise Ratio	>95dB (A-weighted)
Input Sensitivity	200mV (line inputs)
Input Impedance	47kΩ
Power Requirements	120V AC, 60Hz, 200W max
Dimensions (W×H×D)	17.3" × 5.2" × 13.8"
Weight	18.7 lbs (8.5 kg)
Operating Temperature	41°F to 95°F (5°C to 35°C)

Installation Procedures

Proper installation guidelines for optimal performance and safety.

1. Unpack and inspect all components for shipping damage.
2. Place unit on stable, level surface with adequate ventilation.
3. Connect speakers using appropriate gauge speaker wire.
4. Connect audio sources to corresponding input jacks.
5. Connect power cord to grounded AC outlet.
6. Ensure all connections are secure before powering on.

WARNING! Ensure proper ventilation around unit; minimum 4 inches clearance on all sides. Use only with grounded AC outlet.

Front Panel Controls

Description and function of all front panel controls and indicators.

Control/Indicator	Function
POWER Button	Main power on/off switch
VOLUME Knob	Master volume control
INPUT Selector	Selects between CD, AUX, TUNER, PHONO inputs
BASS Control	Adjusts low frequency response (±10dB)
TREBLE Control	Adjusts high frequency response (±10dB)
BALANCE Control	Adjusts left/right channel balance
LOUDNESS Switch	Engages loudness compensation
HEADPHONE Jack	3.5mm stereo headphone output
POWER Indicator	LED indicates power status
PROTECTION Indicator	LED indicates protection mode activation

Rear Panel Connections

Complete overview of rear panel input/output connections.

1. SPEAKER TERMINALS: A/B speaker outputs with binding posts
2. CD INPUT: RCA jacks for CD player connection
3. AUX INPUT: RCA jacks for auxiliary audio sources
4. TUNER INPUT: RCA jacks for AM/FM tuner
5. PHONO INPUT: RCA jacks for turntable (MM cartridge)
6. TAPE REC/PLAY: RCA jacks for tape deck recording/playback
7. AC POWER CORD: Detachable IEC power cord
8. GROUND TERMINAL: Turntable ground connection

Note: Ensure proper impedance matching when connecting speakers. Use only recommended speaker impedance (4-16Ω).

Operation Instructions

Detailed operating procedures for normal use.

1. Power on unit using front panel POWER button.
2. Select desired input source using INPUT selector.
3. Adjust volume to minimum before starting playback.
4. Begin playback on source component.
5. Adjust volume to comfortable listening level.
6. Use tone controls to adjust sound characteristics.
7. For headphone use, plug into front panel jack.
8. Power off unit when not in use.

CAUTION! Avoid operating at maximum volume for extended periods. Allow unit to cool between extended use sessions.

Maintenance & Service

Routine maintenance procedures and service intervals.

• Cleaning: Use dry, soft cloth only for exterior surfaces
• Ventilation: Keep ventilation openings clear of obstructions
• Internal Cleaning: Qualified technician only - every 2 years
• Contact Inspection: Check input/output connections annually
• Component Testing: Performance verification every 3 years
• Lubrication: Control shafts and switches as needed

WARNING! Disconnect power before any internal maintenance. Internal service by qualified personnel only.

Circuit Diagrams

Reference circuit diagrams for technical service.

Complete schematic diagrams including:

• Main amplifier circuit
• Power supply section
• Pre-amplifier stage
• Tone control circuits
• Protection circuitry
• Input selector switching

Note: Circuit diagrams are for qualified service technicians only. Refer to separate schematic documentation for detailed diagrams.

Troubleshooting Guide

Common issues and recommended solutions.

Symptom	Possible Cause	Corrective Action
No power	Power cord disconnected	Check power cord connection; verify outlet function
No sound	Input selection incorrect	Verify input selector position; check source device
Distorted audio	Overload protection	Reduce volume; check speaker impedance
One channel silent	Balance control/Cable	Check balance setting; verify cable connections
Hum/buzz	Ground loop	Check ground connections; separate power cords
Protection mode	Short circuit/Overheat	Check speaker wires; allow unit to cool

Parts List

Replacement parts and components.

Part Number	Description	Notes
MZ-5025-PS	Power Supply Board	Complete assembly
MZ-5025-AMP	Amplifier Module	Left/right channel
MZ-5025-TONE	Tone Control Board	Bass/treble circuits
MP-1027	Volume Potentiometer	50kΩ dual gang
MS-4582	Input Selector Switch	4-position rotary
MF-3361	Power Transformer	120V primary
MC-2254	Main Filter Capacitor	4700μF/63V
ML-8873	Front Panel Assembly	Complete with controls

Safety Information

Important safety precautions and warnings.

• Disconnect power before servicing
• Use only specified replacement parts
• Observe electrostatic discharge precautions
• Verify correct line voltage before operation
• Ensure proper grounding of all equipment
• Keep flammable materials away from unit
• Do not operate with covers removed
• Follow local electrical codes for installation

DANGER! High voltages present inside chassis. Capacitors may retain charge after power disconnection.

Warranty & Support

Warranty information and technical support contacts.

Warranty Period: 3 years from date of purchase

Warranty Coverage: Parts and labor for manufacturing defects

Service Centers: Authorized Marantz service centers worldwide

Technical Support: Available Monday-Friday, 9:00 AM - 6:00 PM EST

Contact Information:

• Phone: 1-800-MARANTZ (1-800-627-2689)
• Email: [email protected]
• Website: www.marantz.com/support
• Address: Marantz America, LLC, 1100 Maplewood Drive, Itasca, IL 60143