Onkyo A-809 - Service Manual

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Summary

Service Manual Introduction and Safety

Safety-Related Component Warning

Critical components for fire/shock risk require replacement with specified parts.

Specifications and Precautions

Technical Specifications

Detailed performance metrics including power output, distortion, sensitivity, and frequency response.

Precautions for Use and Maintenance

Guidelines on fuse replacement, insulation resistance measurement, and voltage selector usage.

Adjustment Procedures

Preparation and Setup for Adjustments

Instructions for workbench setup, including load, signal, and switch configurations.

Idling Current Adjustment

Procedure for adjusting idling current using test points and semi-fixed resistors.

Protection Circuitry Operation Check

Steps to verify the operation of the protection relay and DC detection circuitry.

Microprocessor IC Block Diagram

Microprocessor Pin Function Descriptions

Detailed explanation of each pin's function for the TMP47C440AN microprocessor.

Microprocessor and Motor Drive IC Details

Microprocessor Pin Functions (Continued)

Further pin descriptions for the microprocessor, including input/output selectors and mode controls.

Detailed Block Diagram Components

Printed Circuit Board Parts Lists

Printed Circuit Board Components (Continued)

Printed Circuit Board Components (Further)

Schematic Diagrams

AC 120 V Type Schematic

The main schematic diagram for the AC 120V model of the amplifier.

Schematic Diagram Continuation

Power Supply and Component Schematics

This document is a service manual for the Onkyo Integrated Stereo Amplifier, Model A-809.

Function Description

The Onkyo A-809 is an integrated stereo amplifier designed to deliver high-quality audio output. It incorporates a microprocessor (TMP47C440AN) for control and management of various functions, including input selection, volume control, and protection circuitry. The amplifier features multiple input terminals for various audio sources such as Phono (MM/MC), CD, Tuner, Tape Play, and Aux. It also includes output terminals for tape recording and speaker connections. The unit is equipped with protection circuitry to safeguard against fire and electric shock, and it includes a relay system for speaker protection.

Important Technical Specifications

Power Output:

105 watts per channel, minimum RMS, into 8 ohms, with both channels driven from 20 Hz to 20 kHz, and no more than 0.008% Total Harmonic Distortion.

Dynamic Power:

303 watts into 2 ohms
235 watts into 4 ohms
155 watts into 8 ohms

Total Harmonic Distortion:

0.008% at rated power
0.008% at 1 watt output

Intermodulation Distortion:

0.005% at rated power

Damping Factor:

150 at 8 ohms (1 kHz)

Input Sensitivity/Impedance:

Phono (MM): 2.5 mV/50 kohms
Phono (MC): 160 µV/130 ohms
CD: 150 mV/30 kohms
Tuner: 150 mV/30 kohms
Tape Play: 150 mV/30 kohms

Output Level/Impedance:

Tape Rec: 150 mV/1.0 kohms (Phono)

Phono Overload:

Phono (MM): 200 mV RMS, at 1 kHz, 0.012% THD.

Tone Control (Vol -20 dB):

Bass: ±8 dB at 100 Hz
Treble: ±8 dB at 10 kHz

High Cut:

6 kHz (6 dB/Octave) (TREBLE min.)

Frequency Response:

CD, Tuner: 2 Hz-50 kHz (+0, -1 dB)

RIAA Deviation:

Phono (MM): ±0.3 dB, 20 Hz - 20 kHz

Subsonic Filter:

20Hz (-3dB, 6dB/Oct)

Signal to Noise Ratio (IHF-A):

Phono (MM): 94 dB (5.0 mV input)
Phono (MC): 75 dB (0.5 mV input)
CD (DIRECT): 107 dB

Attenuator:

-20 dB

Muting:

-∞

Power Supply:

European models: AC230V, 50 Hz
U.S.A & Canadian models: AC120V, 60 Hz
U.K & Australia models: AC240V, 50 Hz
Worldwide models: AC120 and 220V switchable, 50/60 Hz

Dimensions (W x H x D):

455 x 170 x 420 mm (17-15/16" x 6-11/16" x 16-9/16")

Weight:

16.7 kg, 36.8 lbs.

Usage Features

The amplifier supports a wide range of audio sources and offers comprehensive control over sound output. It includes tone controls for bass and treble, a high-cut filter, and a subsonic filter. The input selector allows users to switch between various audio components, while the volume control, attenuator, and muting functions provide precise control over audio levels. The presence of a voltage selector on worldwide models ensures compatibility with different local power supplies, requiring users to set the switch correctly before operation. Remote control initialization is also supported for convenience.

Maintenance Features

Safety-Related Components:

Components identified with a triangle (▲) on the schematic diagram and in the parts list are critical for fire and electric shock risk. These must be replaced with genuine Onkyo parts with the specified part numbers.
Leakage-current or resistance measurements are required to ensure exposed parts are acceptably insulated from the supply circuit before returning the appliance to the customer.

Replacing Fuses:

For continued protection against fire risk, fuses must be replaced only with the same type and rating. Specific fuse part numbers and descriptions are provided for different voltage models (120V, 230V, 240V, 120V/220V).

Insulation Resistance Measurement (U.S.A. model only):

The insulating-resistance tester should be connected between the power supply cable plug and the terminal GND on the back panel. The resistance should be more than 10 MΩ at 500V.

Voltage Selector (Rear Panel):

For worldwide models, the voltage selector switch must be set to match the local power supply voltage using a screwdriver. It is crucial to confirm the switch is fully engaged in either the up or down position before turning on the power. Models without a voltage selector are designed for specific power supplies only.

Adjustment Procedures:

Preparations: Before any adjustments, the unit should be placed on a workbench with adequate space, no load, no signal, volume turned down, speaker switch off, and power switch off. The unit should be cool.
Idling Current Adjustment: After a 10-minute warm-up, adjust R535 (R536 for the right channel) to achieve 15mV±5mV at test point VCT-IID on the NAAF-4209 circuit board.
Protection Circuitry Check:
- Protection Relay Operation: Confirm the relay turns ON approximately 5 seconds after power-on and OFF approximately 0.5 seconds after power-off. The SERVO indicator LED should light simultaneously with the relay turning ON.
- DC Detection and Servo Circuitry Operation: With no load, apply DC+200mV to the CD input terminals after the speaker relay turns ON, and confirm the relay turns OFF. Repeat for DC-200mV input. Do not connect a load or short speaker terminals during this test.
- Signal Input Check: With no load, confirm the speaker relay does not turn OFF when a 2 ohm load is connected and a peak value of 30VP is output. Then, with a 1 ohm load, confirm the speaker relay switches OFF and ON a couple of times before staying OFF. The relay OFF status should not last more than 1 minute and can be canceled by switching the power OFF.