Denon AVR-688

Other manuals for Denon AVR-688

Service Manual368 pages

Specifications2 pages

Questions and Answers:

S
scarlsonSep 3, 2025
Why does my Denon Stereo Receiver have no picture?
- J
  Joe JohnsonSep 3, 2025
  If you're not seeing a picture, consider these possibilities: * Faulty connections: Check the connections between the AVR-688 and monitor. * Incorrect monitor input setting: Set properly. * Incorrect signal conversion: High definition (1080i/720p) and progressive (480p/576p) video signals are not down-converted. Set the player to interlace (480i/576i) signals if using component input connectors with video (yellow) or S-Video output connectors.
D
Dr. Michael MarshallSep 1, 2025
What to do if my Denon Stereo Receiver is not working properly when using the remote control?
- C
  Crystal TuckerSep 1, 2025
  If your remote control isn't working as expected, here are a few things to check: * Worn batteries: Replace with new batteries. * Out of range: Operate within the specified range. * Obstacle: Remove any obstacle between the main unit and the remote control unit. * Incorrect battery direction: Insert the batteries in the proper direction, following the polarity marks in the battery compartment. * Strong light interference: Move the set to a place in which the remote control sensor will not be exposed to strong light. * Remote ID mismatch: Set “Remote ID” for the main unit to “1.”
J
Jonathan MortonAug 31, 2025
What to do if my Denon Stereo Receiver power turns off suddenly and the power indicator flashes red?
- C
  Connor GriffinAug 31, 2025
  This usually indicates the protection circuit has been activated. This can happen due to several reasons: * The internal temperature is too high: Turn off the power, wait for the unit to fully cool down, and then turn it back on. * Speaker wires are touching: Unplug the power cord, twist the core wires tightly or terminate the speaker cables, and then reconnect them. * Incorrect speaker impedance: Use speakers with the specified impedance. * The set is damaged: Turn off the power and contact a DENON service center.
M
Mark RobbinsAug 29, 2025
Why are HDMI audio signals not output from speakers on my Denon Stereo Receiver?
- W
  Walter McmahonAug 29, 2025
  The audio signal input to the HDMI input connector cannot be played on the AVR-688. Input the audio signal to the digital audio input connector or analog audio input connector.
A
Anthony HendrixAug 27, 2025
Why is there no sound coming from the subwoofer of my Denon Stereo Receiver?
- P
  Patrick FrazierAug 27, 2025
  If your subwoofer isn't producing sound, try the following: * Make sure the subwoofer’s power is turned on. * Check that the “Subwoofer” setting at “Speaker Setup” is set to “Yes.” * Verify the subwoofer is properly connected. * Adjust the subwoofer’s volume to an appropriate level.
A
Austin ChenAug 26, 2025
Why is there no sound coming from the surround back speaker on my Denon Stereo Receiver?
- C
  Charles BlakeAug 27, 2025
  If you're not hearing sound from the surround back speaker, check these settings: * Ensure the surround back speaker’s power amplifier is correctly assigned to the appropriate channel. * Verify the Surround back speaker setting is something other than “None.” * Confirm that the surround mode is set to a mode for 6.1- or 7.1-channel playback.
J
Jeanette PotterAug 25, 2025
Why is there no sound coming from the surround speakers on my Denon Stereo Receiver?
- J
  James RiveraAug 25, 2025
  If you're not getting sound from your surround speakers, it might be because the surround mode is set to “STEREO” or “DIRECT.” Set to a surround playback mode.
D
Darin OlsonAug 22, 2025
Why is there no sound coming from the center speaker of my Denon Stereo Receiver?
- S
  Sheila HopkinsAug 22, 2025
  If you're not hearing sound from the center speaker, and you are playing a monaural source (TV, AM radio broadcast, etc.) in the “STANDARD” (Dolby/ DTS Surround) mode, ensure the mode is set to something other than “STANDARD” (Dolby/ DTS Surround).

Denon AVR-688 Specifications

General

HDMI Outputs	1
Total Harmonic Distortion	0.08 %
Input Sensitivity	200 mV
Tuner Bands	AM/FM
HDMI Switching	Yes
Power Output (per channel)	90 Watt
Audio Formats Supported	Dolby Digital
Response Bandwidth	10Hz - 100kHz
Input Impedance	47 kOhm
Frequency Response	10Hz - 100kHz
Inputs	HDMI
Outputs	HDMI

Summary

Safety Instructions

Getting Started Guide

Initial Setup and Preparations

Part Identification

Front Panel and Display Overview

Rear Panel Connections

Audio, Video, and HDMI Ports

Connectors for audio, video, component, HDMI, and dock connections.

Power, Antenna, and Zone Outputs

Ports for power cord, FM/AM antennas, and ZONE2 audio output.

Connection Preparations

General Connection Guidelines

Speaker Installation Guide

Speaker Placement and Configuration

Surround Back Speaker Placement

Speaker Layout Examples

Speaker Connection Guide

Speaker Cable Connection

Detailed steps for connecting speaker cables and understanding protection circuit.

HDMI Connection Guide

HDMI Usage and Converter Notes

Guidelines for HDMI connections, including signal types and converter cables.

Monitor Connection

Monitor Connection Details

Playback Component Connection

DVD Player and HDP Connection

Connecting DVD players and High-Definition Players to the unit.

CD Player Connection

CD Player Cabling and Setup

iPod Connection

iPod Dock and Input Setup

TVCable Tuner Connection

Tuner Audio and Video Cabling

Recording Components Connection

Video Cassette Recorder Connection

XM Radio Connection

XM Ready Receiver Setup

Antenna Connection Guide

FMAM Antenna Setup

Instructions for connecting FM antenna, AM loop antenna, and related grounding.

Multi-zone Setup Guide

ZONE2 Output Connection

Power Cord Connection

Power Cord and AC Outlet Use

Auto Setup Guide

Auto Setup Preparations

Steps for preparing the unit and microphone for auto setup.

Listening Position and Microphone

Explanation of the main listening position and microphone setup.

Auto Setup Procedure

Subwoofer Pre-Setup

Adjustments for subwoofer use before starting auto setup.

Speaker Detection and Measurement

Steps 1 & 2: Detect speaker connections and measure room acoustics.

Auto Setup Calculation and Errors

Calculation and Parameter Check

Steps 3 & 4: Analyze measurements and check results.

Error Message Troubleshooting

Troubleshooting common error messages encountered during auto setup.

System Setup Guide

System Setup Operations

How to navigate and perform settings within the System Setup menu.

System Setup Menu Examples

Display examples of various settings within the System Setup.

Speaker Setup Options

Speaker Configuration and Size

Manually set speaker size, presence, and subwoofer connection.

Subwoofer Mode Settings

Configure subwoofer's role in reproducing low-range and LFE signals.

Speaker Distance and Crossover Settings

Speaker Distance Measurement

Measure and set the distance from listening position to each speaker.

Crossover Frequency Selection

Choose the crossover frequency for the subwoofer's low-range signal.

Test Tone Adjustment

Test Tone Method and Start

Select playback method and start test tones for volume calibration.

Input Setup Guide

HDMI and Digital Input Assignment

Assign HDMI and digital input connectors to specific sources.

Input Source Assignments

iPod and Component Input Assignment

Assign iPod dock and component video inputs to sources.

Input Setup Details

Audio Delay, Video Convert, Subwoofer Level

Adjust audio delay, enable video conversion, and set EXT. IN subwoofer level.

Radio Tuning Features

Auto Preset Memory

Antenna Aiming for XM Radio

Option Setup Menu

Amp Assign and Volume Control

Configure amplifier assignments and volume settings.

2 chStereo Custom Settings

2 chStereo Customization

Subwoofer and Distance Settings

Subwoofer Mode Selection

Configure the subwoofer's role in reproducing low-range and LFE signals.

Front Speaker Distance Adjustment

Set the distance from listening position to front left and right speakers.

Crossover Frequency Selection

Crossover Frequency Setting

Choose the crossover frequency for the subwoofer's low-range signal.

Surround Mode Configuration

Auto Surround Mode and Room EQ

Memorize surround modes, set room equalization targets.

Direct Mode, Remote ID, and Playback Modes

Configure Direct Mode, Remote ID, and select surround playback modes.

DSP Simulation Playback

DENON Surround Modes Explained

Multi-channel Source Playback

Standard and Input Compatibility

Stereo and Direct Playback Modes

Stereo and Direct Playback Explained

Surround Parameter Adjustments

Mode, EQ, Compression, LFE Settings

Adjust surround mode, EQ, compression, and LFE levels.

Image, Dimension, Delay, Effect Settings

Configure center image, dimension, delay time, and effect level.

Room Size and Tone Control

Set room size simulation and adjust bass/treble tone controls.

Surround Back Channel Output Options

Multi-channel and 2-Channel SB CH OUT

Tone Control Settings

Tone Defeat and BassTreble Adjustment

Room Equalization Settings

Room EQ Options Explained

Select desired room equalization targets like Audyssey or Flat response.

Audio Enhancement Features

RESTORER Functionality

Playback Operations Guide

Power, Input Source, and Mode Settings

Procedures for powering on/off, selecting sources, and setting input modes.

Volume Adjustment

Radio Station Presets

Presetting and Listening to Stations

iPod Playback Guide

iPod Music Playback Operation

iPod Usage Notes and Features

Quick Select Function

Storing and Recalling Settings

Remote Control Operations

Controlling DENON and Other Components

Button Functions by Component

Front Remote Button Mapping

Rear Remote Button Functions

Rear Remote Button Mapping

Amp Assign and Multi-zone Setup

Multi-zone Settings with Amp Assign

Playback Mode Settings

Bi-Amp and Multi-zone Operations

Bi-Amp Connection Setup

Zone Output Preparation

Multi-zone Operations Guide

Zone 2 Power, Source, and Volume

Surround Mode Parameter Guide

Parameter Adjustability Overview

Surround Mode Input Signal Differences

Input Signal Compatibility Chart

Troubleshooting Guide

General Unit Troubleshooting

Solutions for common problems like power, sound, or display issues.

Remote Control Troubleshooting

Solutions for problems related to the remote control unit's operation.

Audio Troubleshooting

Speaker Sound Troubleshooting

Video Troubleshooting

Picture and Connection Troubleshooting

iPod and XM Radio Troubleshooting

iPod Playback Troubleshooting

XM Radio Reception Troubleshooting

Technical Specifications

Audio and Video Specs

Tuner, General, and Remote Specs

Remote Control Preset Codes

DVD, VDP, VCR, Cable, TV Codes

Recorder and CD Player Codes

Related product manuals

Denon AVR 689 - AV Receiver

Table of Contents

Other manuals for Denon AVR-688

Questions and Answers:

Denon AVR-688 Specifications

Summary

Safety Instructions

Getting Started Guide

Initial Setup and Preparations

Part Identification

Front Panel and Display Overview

Rear Panel Connections

Audio, Video, and HDMI Ports

Power, Antenna, and Zone Outputs

Connection Preparations

General Connection Guidelines

Speaker Installation Guide

Speaker Placement and Configuration

Surround Back Speaker Placement

Speaker Layout Examples

Speaker Connection Guide

Speaker Cable Connection

HDMI Connection Guide

HDMI Usage and Converter Notes

Monitor Connection

Monitor Connection Details

Playback Component Connection

DVD Player and HDP Connection

CD Player Connection

CD Player Cabling and Setup

iPod Connection

iPod Dock and Input Setup

TVCable Tuner Connection

Tuner Audio and Video Cabling

Recording Components Connection

Video Cassette Recorder Connection

XM Radio Connection

XM Ready Receiver Setup

Antenna Connection Guide

FMAM Antenna Setup

Multi-zone Setup Guide

ZONE2 Output Connection

Power Cord Connection

Power Cord and AC Outlet Use

Auto Setup Guide

Auto Setup Preparations

Listening Position and Microphone

Auto Setup Procedure

Subwoofer Pre-Setup

Speaker Detection and Measurement

Auto Setup Calculation and Errors

Calculation and Parameter Check

Error Message Troubleshooting

System Setup Guide

System Setup Operations

System Setup Menu Examples

Speaker Setup Options

Speaker Configuration and Size

Subwoofer Mode Settings

Speaker Distance and Crossover Settings

Speaker Distance Measurement

Crossover Frequency Selection

Test Tone Adjustment

Test Tone Method and Start

Input Setup Guide

HDMI and Digital Input Assignment

Input Source Assignments

iPod and Component Input Assignment

Input Setup Details

Audio Delay, Video Convert, Subwoofer Level

Radio Tuning Features

Auto Preset Memory

Antenna Aiming for XM Radio

Option Setup Menu

Amp Assign and Volume Control

2 chStereo Custom Settings

2 chStereo Customization

Subwoofer and Distance Settings

Subwoofer Mode Selection

Front Speaker Distance Adjustment