ARCAM FMJ CD23 Compact Disc Player SERVICE MANUAL

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CD23 (Text) Service Guide
Fault diagnostics
Fault No power No Audio output Action Check mains fuse Check power supply rails Check for digital output, if ok then check power supply voltages Check DAC chip Check Dac chip Check supply to remote circuit Check remote flex foil cable Check for +4.9volts on RX201 o/p Check mech supply Check clock signal Caused by failure of clock signal to the mech Check mech supply Check clock signal Check filament voltage 3.1vac Check flex foil cable Check for dry joints on micro and display Check for dry joints on display board

Intermittent noise on output Fails to respond to commands

Fails to read disc Laser optic moves to end stop position

No Display

Spurious display readout

Power supply test points
Position DGND PL202 PL204 IC200 o/p IC203 o/p IC202 o/p IC204 o/p Between R227 & R228 Voltage 0 volts +12 volts -12 volts +7.3 volts - mech supply +5 volts - DAC supply +5 volts - Digital supply -30 volts 3.1 volts AC ­ display filament

Hints & tips
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Voltage conversion 230/115VAC by changing the internal fuse position and fitting the correct rated fuse. 100VAC requires a different transformer.

Main Board L935
Contents

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Circuit description

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Component overlay

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Parts list

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Circuit diagrams

CD23 (text) Circuit Description
Power Supplies Transformers
115/230 VAC: ! Main board - part number L859TX ! Toroid - part number L860TX 100 VAC: ! Main board - part number L862TX ! Toroid - part number L883TX Main board transformer secondary windings: 1. 9V-0V-32V to produce the digital, motor drive and fluorescent display grid supplies +11V(U) Unregulated supply for relay drive and +5V(D) supply +7V (IC200) Mechanism and motor driver supply +5V(D) (IC202) General digital logic supply +5V(A) (IC203) Supply to DAC -30V (IC204) Display grid voltage. 0-5V to provide an AC supply for the display filament.

Clock Buffering
The clock and data signals LRCK, ADATA and BCLK from the mechanism connector SK300 are double buffered by IC300 before being delivered to the DAC.

Power-On/Reset
The power-on reset signal XRST (or RESET) is generated by R409, C410 and IC404. When the power is turned on, C410 is initially uncharged and pin 11 of IC404 is at high voltage, and thus the output is low. After a short time, C410 is charged via R409; IC404 pin 11 is then low, and the output switches high (RESET is de-asserted).

System Clock
The system clock is generated on the DAC board. The clock and data signals LRCK, ADATA and BCLK from the mechanism connector SK300 are double buffered by IC300 before being delivered to the DAC. The system clock is delivered to the mech via two-position jumper PL300.

2.

Microcontroller & Display Board
The system microcontroller IC100 serves the following functions: ! ! ! ! ! ! Control of the mechanism & decoder on the CDM14 mechanism Control of mute, attenuation and de-emphasis for the DAC Direct drive of the fluorescent display Remote control decoding Keyboard scanning DAC muting

Toroid transformer secondary winding: 1. 13.7-0V-13.7 for audio output circuitry (DAC)

Relay Mute Control
This circuit drives a relay to un-mute the analogue output ~5 seconds after the unit is powered on, and quickly mutes the output when the unit is switched off. The circuit works effectively as an "AND" gate. If AC is present on the transformer secondary winding and the 5second timer composed of R222 and C221 has reached the threshold voltage (Vbe of TR200 + Vbe of TR201 - Vce of TR202, or ~1.0V), the relay coil is connected to +11V (referenced to 0V_3 as required by the DAC's internal circuitry) via TR204. When AC is removed, C231 discharges quickly through R225, the base voltage of TR204 rises and the relay coil voltage is removed, muting the output. TR203 resets the `timer' by discharging C221 quickly at turn-off.

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, which the micro is pre-programmed to interpret accordingly. The remote control data contains a `Customer Code' that identifies this as an Arcam product. The diode network D100 to D106 configures the micro to accept this code.

Remote Control/PIC Micro
Remote control data is received from the IREye on the display PCB and buffered by TR300 and TR301. The Programmable Interrupt 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.

Remote Bus Carrier Filter & Demodulator
Remote control commands can be delivered over wire to SK500 for multi-room applications. Incoming signals are attenuated and clipped by resistors and D500. L500 and C508 form a parallel resonant circuit at approximately 37kHz. This demodulates the incoming signal and the output is passed to IC501A where it is `chopped', low pass filtered and fed to IC501B to provide the RC5 output signal.

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 IC303.

Digital Output
The decoder on the mechanism assembly generates an SPDIF format digital output signal. This is passed to buffer IC500A. IC500B through E are used in parallel to provide a transformer less 75-ohm source impedance to a single phono socket SK501. Optical digital output via IC502 is also tapped off the digital output signal via IC500F.