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DGX-650B/WH

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Contents

Contents

Line upMain Topics to Service

Circuit Boards Changes

Power controlDigital amplifier & Volume Control

AUX-IN Function

Disassembly Procedure

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Line-Up DGX-650

DGX-650B

DGX-650WH

LP-7AWH (* Added color variation)

DGX-640C

DGX-640W

DGX-650B

New Color

DGX-650WH

Discontinued

Discontinued

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Main Topics to Service

I. Circuit Boards Changes

II. Digital Amplifier & Volume ControlIII. Power control

IV.AUX-IN Function

V. Disassembly Procedure

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Block Diagrams DGX-650

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Circuit Boards Changes 1/2

Changes from the DGX-640

The AM circuit board is removed.The AJACK circuit board is installed.

The amplifying function is transferred to the DM circuit board.

The AJACK circuit board has H-pass filter and the ERP control function.

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Circuit Boards Changes 2/2

DGX-650 DGX-640

Removed

Added

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DGX-640

Power on/off is controlled by the latch type switch.

DGX-650

Power on/off is controlled by the non-latching switch.

Power control (ERP control function)

CPUAC Adaptor RegulatorDC

CPUAC Adaptor Regulator

SW

SW

Controlled out here

Controlled here

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Stand by switch mechanism

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Stand by switch mechanism

PSWO

/PSWI

+B VCPU3.3V

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Trouble: Cannot be turned off

Model

DGX-650 or the products that have stand-by power system.

Symptom

The instrument can be tuned on but cannot be turned off.

Cause

Hi impedance at the switch due to the bad switch.

SolutionCheck the switch and replace the switch if needed.

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In the case of the switch is bad

PSWO

/PSWI

+B VCPU3.3V

In this case, the PSWO port does not become low enough.

Therefore the CPU cannot detect that the switch is pushed.

Bad switch means that the switch has some impedance.

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Digital amplifier

Volume Control 1/2

Changes from the DGX-640

I. The analog power Amp ICs are removed.

II. The digital power Amp IC, YDA164C is added.

III. The headphone output is amplified by HP Amp.

IV. Sound signals do NOT pass through the master volume.

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Digital amplifier

Volume Control 2/2

Vol Location Data

Voltage value

A/D

Block Diagram of the DGX-650

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AUX-IN Function 1/2

AUX-IN is added to the DGX-650.

I. Audio data are converted to digital data by ADC.

II. The ADC (IC16) is located on the DM circuit board.

III. The AUX-IN data is mixed by the CPU (SWX08).

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AUX-IN Function 2/2

,

Vol Location Data

Voltage value

A/D

Block Diagram of the DGX-650

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Disassembly Procedure

Very similar to the DGX-640.

Start from the bottom.

Take out all the screws except 2 screws.

Refer to the Service Manual for the DGX-650.

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END