Onkyo TX-7230 - Circuit Descriptions; Synthesizer and Controller Operation

TX-7230
CIRCUIT DESCRIPTIONS
1. Synthesizer and controller operation
Pin
No.
{|
Symbol
Terminal
Description
1
GND
Ground
2
XT
X’tal
Connected to the 7.2MHz crystal oscillator for the reference frequency.
FM band specification
input
MW band specification
input
LW band specification
input
Mutual reset type, performs switching of each band, FM/MW/LW.
Manual tuning mode
specification input
MANUAL
—-|-__—
8 AUTO
specification input
Auto search tuning mode
Mutual reset type, performs auto search and manual operation mode
switching during UP/DOWN tuning.
p10 DOWN DOWN tuning key input
Memory store command
input
Preset memory channel
a a a specification input
Connect the push key and perform UP/DOWN tuning.
The preset memory is set to the write mode when the key is pressed.
Controls the write and read out of the internal 16-station preset
memory along with the MC] and MC2 input.
MC-1
Set the
16-station
preset
memory
to
the
8
FM/8
AM
station
mode
or
Memory
control
input
the
FM/MW/LW
3-band
16-station
random
mode.
The
8
FM/8
AM
MC-2
mode
is
used
in
this
unit.
Osc?
AM
oeallaton
eaaninal
CR
connection
terminal
for
the
oscillator
that
determines
the
scan
speed
during
the
AM
search
mode.
—t
al
2
:
:
CR
connection
terminal
for
the
oscillator
that
determines
the
scan
os!
le
oscillator
terminal
speed
during
the
FM
search
mode.
Output
that
represents
the
SOkHz
FM
band
tuning
step
for
European
o/s
EM
SORHE
output
models.
Goes
to
the
high
level
for
the
50
kHz
setting.
7
CK2
CK
Tuned
frequency
Outputs
the
serial
data
and
timing
clock
to
the
tuned
frequency
display
data
output
driver.
28
MUTE
Muting
signal
output
Goes
to
the
high
level
during
muting
output.
Regin specification input
29 E2
30 El
See table 1.
AM IF signal input
ae |
31
STOP
3
During
AM
reception,
this
counts
the
IF
signal
and
stops
auto
search.
ae
;
3
STOP
2
Auto
search
stop
When
the
stop
|
input
(pin
33)
is
at
the
high
level
and
this
terminal
2
signal
input
goes
to
the
high
level,
auto
search
is
stopped.
|
=,
: .
. .
*
d
.
33
STOP
1
Scan
speed
slow
input
When
the
high
level
is
input
at
this
terminal,
the
auto
search
speed
is
cut in half.