Arcam Diva CD72, Diva CD92 Schematic

Service Manual

CD72/92

DiVA CD72, CD92 Compact Disc Player

Issue 1.0

ARCAMARCAM

Contents List

Contents list

Circuit description

Upgrade procedure

Service guide

Circuit diagrams

Component overlays

Circuit board parts list

General assembly parts list

CD72/CD92 Circuit Description

SUMMARY

The Main PCB for the DiVA CD72/92 player may be built as two different versions:

! With all components fitted for the Alpha CD72

(L887RS)

! With audio components and connectors omitted, for

use as a motherboard for plug-in DAC module L816 (L888RS) for CD92

The CD72 version may be converted for use with a upgrade plug-in DAC board by removing a configuration connector.

The system is based on a Sony kit, comprising CDM14-5BD10 laser mechanism & loader, micro-controller and fluorescent display.

The PCM 1716, as per the 1710, can be operated in either Software or Hardware mode. The default for the CD72 is hardware mode.

Power Supplies & Reset/Mute

Selection for 230V or 115V mains operation is made by inserting a fuse into the appropriate position. The mains transformer has three secondary windings:

1. Provides +12V and -12V supplies for the audio output circuitry via regulators Z204 and Z205.

2. This produces the digital, motor drive and fluorescent display grid supplies:

+7.3V (Z206) Mechanism and motor driver supply +5V (Z208) General digital logic supply +5V (Z207) Supply to DAC +5V (Z203) Supply to system clock generator

-30V (Z209) Display grid voltage.

3. Provides an AC supply for the display filament.

The power-on reset signal XRST is generated by R17 and C29. When the power switch is turned off one of its poles discharges C29 quickly. This, along with the AMUTE signal from the micro, controls the output mute transistors via level shifter Q3.

Remote Control/PIC Micro

The PIC micro controller converts the RC-5 format data into the NEC format required by the Sony micro. The PIC also controls the configuration of the digital filter/DAC on the DAC board.

Micro controller & Display Board

The system micro controller Z212 has the following functions:

! Control of the mechanism & decoder on the CDM14 ! Control of mute, attenuation and deemphasis for the

DAC

! Direct drive of the fluorescent display ! Remote control decoding ! Keyboard scanning

The keyboard scanning works by connecting the keys to a resistor ladder on an ADC input to the micro. Pressing a key presents a unique voltage to this input.

The remote control data contains a ‘ Customer Code’ that identifies this as an Arcam product. The diode network D291 to D297 configures the micro to accept this code.

Motor Driver

The status of the drawer is indicated to the micro by two micro switches ‘ INSW’ and ‘ OUTSW’ on SK205. The micro controls the drawer motor via driver Z210.

DAC & System Clock

The DAC is a Burr Brown PCM1716. Mute, attenuation and deemphasis functions can be controlled via a 3-wire serial link from the system micro to pins 26, 27 & 28 via resistors R31 R32 & R33 respectively. Currently resistors R31 to R33 are not fitted and the DAC is configured for hardware control.

Digital audio is input on pins 1, 2 & 3 in standard Sony format, i.e. Word Clock, Bit Clock and Data.

The system clock is based around 16.9344 MHZ crystal X1 and transistor Q2. This produces a stable clock with low jitter. Z202E & D provide amplification and buffering to the DAC.

Analogue Filters

Z1A (& Z101A) provides the basis for a 2-pole filter. Z1B (& Z101B) buffer the audio and set the output level.

Digital Output

An SPDIF format digital output signal is generated by the decoder on the mechanism assembly. This is passed through isolating transformer T202 to a single phono socket SK5. Optical digital output via Z2 is also tapped off the digital output signal. Power is supplied to Z2 via Z3 a 78L05 regulator.

Upgrade to CD92

The CD72 includes a configuration PCB connected to PL1. This provides power to the DAC and clock generator, connects the digital audio and system clock signals to the DAC and provides additional clock buffering with Z4 A&B .

Removing this board removes these connections and allows the system clock generated on the DAC board to pass through to the CDM14.

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