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ALPHA 7/8/9 CD SERVICE MANUAL
ALPHA 7/8/9 CD SERVICE MANUAL
Disc Transport Module
The CDM 14 module comprises the disc loading
mechanism, laser assembly, RF amplifier and
analogue signal processing. All the servo control and
motor drive circuits are also included.
Digital Signal Processor
Mute, attenuation and de-emphasis functions are
controlled via a three-wire serial bus from the system
controller (Z212) to pins 26, 27 & 28 of the DAC
(Z201).
Digital audio is input to the DAC on pins 1, 2& 3 in
standard Sony format i.e. Word Clock, Data and Bit
Clock.
A digital output complying to the SPDIF standard is
generated by the decoder on the mechanisim
assembly. This is passed through an isolating
transformer, T202, to the digital output socket SK5.
System Controller
The CXP826P16Q system controller (Z212) is a
combined CD player controller, keyboard scanner,
remote control decoder and fluorescent display
driver. It's clock is generated by 4.00MHz resonator
X201.
The controller detects the position of the disc drawer
from the status of
OUTSW, on socket SK205. The drawer motor is
controlled via motor driver Z210
The keyboard scanning works by connecting the keys
to a resistor ladder on an ADC (analogue to digital
convertor) input to the microcontroller. Pressing a
key presents a unique voltage to this input.
The signal from the remote control receiver is input
to RMIN (pin 2) after first passing through the PIC
microcontroller, Z211, on the small remote receiver
pcb. This PIC ic converts the RC-5 format codes
from the remote control handsets to NEC data,
suitable for the Sony chipset. It also controls
theconfiguration of the digital filter/DAC on the Alpha
8 and 9 DAC boards the The remote control data
contains a 'customer code' that identifies it as an
Arcam product.The microcontroller is confiqured to
accept this code by means of the diode network
D291 to D297.
Disassembly For Servicing
To remove the boards within the CD players follow
the instructions below.
1.
Remove the top cover.
2.
Press load to eject the CD tray.
two microswitches, INSW &
3.
Unplug the unit from the mains.
4.
Push the tray front upwards to remove it
from the tray. Push the tray in manually.
5.
Remove the 4 screws holding the front panel
to the chassis and release the locating tabs.
6.
Unplug the flexfoil from the display board
where it enters the main pcb.
7.
Remove the 2 screws holding the remote
receiver pcb in place.
8.
The front panel can now be pulled off the
unit.
9.
To remove the display pcb remove the 6
screws holding the board in place.
To remove the main pcb first remove the DAC board
if it is an Alpha 8 or 9 CD player.
1.
Remove the 3 screws holding the audio
output sockets to the rear panel and 2
screws holding the aluminium extrusion in
place.
2.
Squeeze the tops of the 2 pcb pillars and lift
the board up slightly to clear them .
3.
Remove the 2 flexfoils from the DAC board.
The DAC board, still attached to the extrusion, can
now be removed from the unit.
To remove the main pcb remove the 8 pcb securing
screws and the screw holding the digital ouput socket
to the chassis. (On Alpha 7 CDs also remove the 3
screws securing the audio ouput sockets in place).
Release the cables which connect the mechanism to
the main board.
The main pcb can now be slid out of the case.
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