Marantz 2230 Service Manuals

The Marantz 2230 is a classic stereo receiver from the 1970s featuring 30 watts per channel, high-quality analog components, and the distinctive Marantz blue dial. This service manual covers technical specifications, circuit diagrams, alignment procedures, troubleshooting guides, and maintenance instructions for professional technicians and qualified service personnel.

1. Technical Specifications 2. Block Diagrams 3. Circuit Descriptions 4. Alignment Procedures 5. Parts List 6. Schematics 7. PCB Layouts 8. Troubleshooting Guide 9. Voltage Measurements 10. Service Notes 11. Safety Precautions

Technical Specifications

Complete technical specifications and performance characteristics of the Marantz 2230 stereo receiver.

Parameter	Specification
Power Output	30 watts per channel (8 ohms, 20Hz-20kHz)
Total Harmonic Distortion	0.3% at rated output
Frequency Response	10Hz - 50kHz (+1, -3dB)
Input Sensitivity	Phono: 2.5mV; Aux: 250mV
Signal-to-Noise Ratio	Phono: 70dB; Aux: 85dB
Damping Factor	40 at 8 ohms
Tone Controls	Bass: ±10dB at 50Hz; Treble: ±10dB at 10kHz
Power Requirements	120V AC, 60Hz, 180 watts
Dimensions	17-1/8" W × 5" H × 14-1/2" D
Weight	24.2 lbs (11 kg)

Block Diagrams

System block diagrams showing signal flow and functional relationships between circuit sections.

Main System Block Diagram: Overview of entire receiver architecture
Tuner Section Block Diagram: FM/AM tuner signal path
Preamplifier Block Diagram: Phono and line-level signal processing
Power Amplifier Block Diagram: Output stage and protection circuits
Power Supply Block Diagram: Voltage regulation and distribution

NOTE: Refer to schematics for detailed component-level information.

Circuit Descriptions

Detailed descriptions of major circuit sections and their operational principles.

FM Tuner Section: RF amplifier, mixer, IF stages, and multiplex decoder
AM Tuner Section: RF and IF amplification, detector circuit
Phono Preamplifier: RIAA equalization and low-noise amplification
Tone Control Circuit: Bass and treble control networks
Power Amplifier: Complementary symmetry output stage with protection
Power Supply: Transformer, rectification, and filtering circuits

Alignment Procedures

Step-by-step alignment instructions for tuner and amplifier sections.

FM Tuner Alignment: IF transformers, discriminator, and oscillator
AM Tuner Alignment: IF transformers and oscillator tracking
Stereo Decoder Alignment: 19kHz pilot and 38kHz subcarrier
DC Offset Adjustment: Power amplifier balance and offset
Bias Current Adjustment: Output transistor bias setting

WARNING! Use proper test equipment and follow procedures exactly.

Parts List

Complete component listing with manufacturer part numbers and specifications.

Reference Designator	Description	Value/Type	Part Number
Q101-Q104	Transistor	2SC458	Marantz 123-456
R201-R245	Resistor	Various values	Marantz 234-567
C301-C345	Capacitor	Various values	Marantz 345-678
D401-D415	Diode	1S2473	Marantz 456-789
T501	Power Transformer	Primary 120V	Marantz 567-890

Schematics

Complete circuit schematics for all receiver sections.

Main Schematic: Overall receiver circuit diagram
Power Supply Schematic: Transformer, rectifiers, and regulators
Preamplifier Schematic: Phono and line-level input circuits
Power Amplifier Schematic: Driver and output stages
Tuner Section Schematic: FM and AM receiver circuits
Control Section Schematic: Selector switches and tone controls

NOTE: Schematics show component values and test points.

PCB Layouts

Printed circuit board layouts showing component placement and trace routing.

Main Amplifier Board: P000 board component placement
Tuner Board: P100 board layout and connections
Power Supply Board: P200 board component locations
Control Board: P300 board switch and potentiometer mounting
Front Panel Board: Indicator and control wiring

Troubleshooting Guide

Systematic approach to diagnosing and repairing common problems.

Symptom	Possible Cause	Corrective Action
No power	Fuse, power switch, transformer	Check main fuse F001; verify transformer primary voltage
One channel dead	Output transistors, driver stage	Check Q701-Q704; measure DC offset; test driver transistors
Distorted audio	Bias current, leaky capacitors	Adjust bias current; replace electrolytic capacitors in signal path
No FM reception	Tuner section, power supply	Check tuner board voltages; verify oscillator operation
Hum in output	Grounding, filter capacitors	Check ground connections; replace main filter capacitors C001, C002

Voltage Measurements

Reference voltage measurements at key test points throughout the receiver.

Test Point	Expected Voltage	Tolerance	Notes
TP1 (+B)	+35V DC	±2V	Main positive supply
TP2 (-B)	-35V DC	±2V	Main negative supply
TP3 (+24V)	+24V DC	±1V	Tuner supply
TP4 (Offset)	0V DC	±10mV	Amplifier output DC offset
TP5 (Bias)	15mV	±2mV	Output stage bias voltage

Service Notes

Important service tips, common failure points, and modification information.

Common Failures: 2SC458 transistors in phono stage often become noisy
Capacitor Replacement: Electrolytic capacitors in power supply should be replaced during service
Thermal Compound: Reapply thermal compound when replacing output transistors
Alignment Tools: Use non-metallic alignment tools for FM tuner adjustments
Safety: Always use isolation transformer when servicing live chassis

Safety Precautions

Critical safety information for technicians servicing high-voltage equipment.

Disconnect power before replacing components or making measurements
Use properly rated replacement fuses - never bypass fuse holders
Discharge large capacitors before working on power supply
Use isolation transformer when making live measurements
Ensure proper grounding of test equipment and work surface

DANGER! Lethal voltages present - qualified personnel only.

Service Support: For technical assistance contact authorized Marantz service centers.