Arcam DiVA DV78, Service Manual

Page: 4 / 41

The 1V8 rail is derived from the 3V3 rail and is
regulated by the adjustable regulator at location
REG1003 .
The Analogue supply stages arrive at the main board
as +15V3 and –15V3 rails these are filtered L1002 and
L1015 before being regulated by the adjustable
regulators at locations REG1000 and REG1002 to
p/- 12V rails for the Analogue output stage.
Regulator REG1001 is fed from the +15V3 rail and
forms the Audio DAC supply.
The Display board requires several supply voltages
these are simply passed through the main board,
being filtered on the way to prevent transmission of
noise through to the surrounding electronics. The
display takes the +5V, -19V, -13V5 and -9V the –13V5
and –9V form a floating 4.5V supply biased relative to
the –19V grid voltage.
Display Board
The main component of the Display board is IC1 this is
a Vacuum Florescent Display driver with keyboard san
and a serial data in/out interface.
The Chip receives display drive serial data from the
Vaddis V chip on the main board via Con1 on pins 12,
13 and 14 these will be seen a DIN , STS and CLK this
data is used to drive the VFD a DOUT line interfaces
with the VADDIS V and supplies Keyboard Scan
information. The keyboard scan is a 6 x 4 matrix with
the Key Source appearing at S3, S4, S5, S6 and the
Keyscan data returns appearing a K2, K3 and K4.
Please see: above for power supply information.
The Infra red pick-up at location RXI receives RC5
data and send the data to the Vaddis V on the main
board via transistors TR2 and TR3, LED 2 is used to
mix the rear panel RC5.
The rear panel 3.5mm input jack receives modulated
RC5 code; this is filtered for ultra sonic noise by the
inductors at locations L900 and L901 and then passed
to the Infrared diode on the display at location LED2.
Main Board electronics DV78.
Zoran Vaddis V.
The main processor/control chip on the main board is the
Zoran Vaddis V at location IC202 , this is the latest
incarnation of the very popular Vaddis range of processors
and allows for a much lower component count when
compared to our earlier players as many of the playback
functions have moved onto the Vaddis V silicon.
Below you will see the
major functions
of the Vaddis V
when used with the DV78.
o
Decoded Analogue Video output (internal
DAC) used on the DV78 only.
o
SPDIF output.
o
Internal display interface.
o
Internal ATAPI interface.
o
Internal IR interface.
o
Serial in/out for RS232 (Optional).
A more detailed explanation of the Vaddis V and
peripheral components follows.
Vaddis Power
The Vaddis V is powered by two separate supplies the
Vaddis requires a 1.8v supply for the core, this is regulated
from the 3.3v rail by REG1003, the 3.3v rail is used to
supply power to the I/P – O/P ports of the chip.
ATAPI interface
CON203 is an ATAPI interface on a 40 way IDE
connector. This is decoupled from the Drive via an array of
decoupling resistors as required by the ATAPI spec.