Marantz 4240 Owners Manual

The Marantz 4240 is a quadraphonic stereo receiver featuring 4-channel sound reproduction, Dolby Surround compatibility, multiple input/output options, front panel controls for volume, balance, tone adjustments, tape monitoring, and speaker selection. With power output of 40 watts per channel, built-in AM/FM tuner, phono input for turntables, and comprehensive connectivity for home audio systems. Below are key sections for safety, features, installation, setup, operation, and troubleshooting.

1. Features at a Glance 2. Installation 3. First-Time Setup 4. Specifications 5. Controls and Settings 6. Connecting Components 7. Quadraphonic Operation 8. Maintenance & Care 9. Regulatory Information 10. Troubleshooting

Features at a Glance

Key components: Quadraphonic decoder, AM/FM tuner, Phono inputs, Tape monitor circuits, Front/rear speaker outputs, Headphone jack, Tone controls.

Feature	Description
Power Output	40 watts per channel (4 channels)
Input Selector	Phono, Aux, Tuner, Tape 1, Tape 2
Quadraphonic Decoder	4-channel sound reproduction
Tone Controls	Bass and treble adjustment
Loudness Contour	Enhanced sound at low volumes
Speaker Selector	Front/Rear speaker control
Headphone Jack	For private listening
AC Power Cord	Standard power connection
Mode Selector	Stereo/Quadraphonic modes
Balance Controls	Front/Rear and Left/Right adjustment

Installation

Unpack and inspect contents. Place on stable, ventilated surface.

Connect speakers: Match impedance (8 ohms recommended); connect front and rear speakers.
Connect audio sources: Turntable to PHONO inputs; other sources to AUX inputs.
Connect antenna: AM loop antenna and FM dipole antenna for radio reception.
Plug into AC power outlet.

WARNING! Ensure proper ventilation; do not block rear vents. Use correct speaker impedance to avoid damage.

First-Time Setup

Power on receiver; set initial controls to neutral positions.

Set volume control: Turn to minimum before power on.
Select input source: Choose PHONO for turntable, AUX for other sources.
Adjust tone controls: Set bass and treble to flat position initially.
Tune radio: Select AM or FM band; tune to desired station.

CAUTION! Always turn volume down before switching inputs or powering off.

Specifications

Power Output: 40 watts RMS per channel (4 channels)
Total Harmonic Distortion: Less than 0.5% at rated power
Frequency Response: 20Hz - 20kHz ±1dB
Input Sensitivity: Phono: 2.5mV, Aux: 150mV
Signal-to-Noise Ratio: Phono: 70dB, Aux: 90dB
Tone Controls: Bass: ±10dB at 100Hz, Treble: ±10dB at 10kHz
Speaker Impedance: 8 ohms recommended
Power Requirements: 120V AC, 60Hz, 250W
Dimensions: 19" wide × 6" high × 14" deep

Controls and Settings

Front Panel: POWER, INPUT SELECTOR, VOLUME, BALANCE, TONE CONTROLS, MODE SELECTOR, SPEAKER SELECTOR.

Rear Panel: Speaker terminals, Input/output jacks, Antenna connections, AC power cord.

Input Selection: PHONO, AUX, TUNER, TAPE 1, TAPE 2. Mode Selection: STEREO, QUADRAPHONIC, REVERSE. Tone Controls: BASS and TREBLE with center detent. Speaker Selection: FRONT, REAR, FRONT+REAR. Balance Controls: FRONT/REAR and LEFT/RIGHT adjustment.

Connecting Components

Turntable: PHONO inputs. Tape Deck: TAPE inputs/outputs. Other Sources: AUX inputs.

Turn off receiver before connecting components.
Match cable types (RCA for audio, speaker wire for speakers).
Connect antennas: FM dipole for FM, AM loop for AM reception.
Select appropriate input source after connection.

Tip: Use high-quality cables and ensure secure connections for best performance.

Quadraphonic Operation

Supports 4-channel discrete and matrix encoded sources.

Select QUADRAPHONIC mode for 4-channel sources.
Adjust front/rear balance for proper sound field.
Use tape monitor for recording quadraphonic sources.
Reverse mode swaps front and rear channels.
For stereo sources, use STEREO mode with optional surround effects.
Monitor tape recording with TAPE MONITOR switch.
Adjust loudness contour for low-volume listening.
Use headphone jack for private stereo listening.

WARNING! Do not operate with speaker outputs shorted. Ensure proper ventilation during extended use.

Maintenance & Care

Unplug before cleaning. Use soft, dry cloth for exterior; compressed air for controls.

CAUTION! Do not use liquid cleaners; avoid moisture near electrical components. Service by qualified technician only.

Regulatory Information

FCC Part 15: Class B digital device; complies with interference limits for residential use. Copyright © 1974 Marantz; trademarks of Marantz Company. For service information, contact authorized Marantz service centers. Manufactured under license from relevant patent holders.

Troubleshooting

Symptom	Possible Cause	Corrective Action
No sound from speakers	Speaker connections/selector	Check speaker wires; verify speaker selector position.
Distorted sound	Overload/incorrect input	Reduce volume; check input source selection.
No radio reception	Antenna connections	Verify antenna connections; reposition antennas.
Hum or noise	Grounding/cables	Check ground connections; use shielded cables.
One channel silent	Balance control/cables	Adjust balance; check input cables and connections.

Reset: Turn off and unplug for 30 seconds if unit locks up.

Service: Contact authorized Marantz service center for internal repairs.