Revox B261 Serviceanleitung Seite 41

sruotrR
nd/ox
8261 SA
sEcTtoN 3/6+
3.
B
COMMAND
UNIT
3.8.1
Keyboard
The entire keyboard is constructed with a rubber
membrane pad
with built-in contacts.
The
opposite contact is
made
by the
mounting circuit
board implemented in
goJ-d
technology.
The keyboard rs designed as a 5 x B matrix and interrogated
by
scanni-ng.
The five matrix columns of the keyboard and the indicator
LEDs
are controlled through the serial-paralleI interface
SAA1061
(ICl).
The SAAI06I receives its infornation
from the
microprocessor through the
CBUS.
A priority
encoder processes the key matrix row signals
and
supplies them in coded form to the microcomputer.
3.8.2 Display, meters
The signal strength is indicated by a 90'moving coil instrument
that features a dial cafibrated i-n
dByF.
Center tuning is indicated by a 72' moving coil instrument.
A transflective LC drsplay indicates either
the frequency in
MHz, the station
name
or station number, as well as the
functions
MUTING,
STEREO
or
STORE.
It is controlled by a series-
paralJ.el j.nterf ace
LCD
driver
in multiplex 1:2
rnode.
The
LCD
driver receives informatj-on through the
CBUS
from the
microprocessor.
The supply voLtage of the
LCD
is temperature-
compensated.
3.8.3 Level control
The
STATION
and
STEREO
thresholds as well
PHONES
and
VARIABLE
OUTPUT
are adjustable
3.8.4
Remote
control receiver
The
controlfed IR receiver
uses
the Intermetall circuit
package
TEA
1009.
The
subsequent
pulse
shaper
supplies the pulse train
for the interrupt port of the
microcomputer.
as the fevels for
with potentiometers.