Technics ST-9038

PART
II
CIRCUIT
FOR
STARTiAND
STOP
PULSE
GENERATION
tN
AUTO
TUNING, AND
ADJACENT
CIRCUfË
pin@of
lCgl
2
is
connecred
to the
base
of TR1
1
3
through
R143//D108
{
o
+B
D1
08
B l43
TR1 14
To 1C912
Output
Lch
R1 43
TR4O2
TR111
TR1,I3
au to
mo
no
pink
no ¡se
s3-3
R 146
TR4O3
Output
Fì
ch
The
oþeration of
each
transistor
is shown
in
the
following
table
rce12
pin@t@l
Stop Stop
TR 113
ON
OFF ON
rR112 ON OFF
ON
TR114
OFF ON OFF
rR402.403 OFF ON
OFF
Output signal
Present Muted
Present
As
shown
in the
above
table,
T8113
is
OFF
during tuning.
To achieve
this,
it is required
that Vf
of
D108,
be smaller than Ver
of TR113.
Therefore
a
germanium
diode
must be used.
(lf
a silicone
diode is used,
TR1'13
may sometimes
fail to turn OFF.)
2-2 Operations with
station selector
at
fine
and standard
When
the AT button
is
pushed
with the selector set at f¡ne or
standard
position,
the
station will be
automatically
selected.
The
fine
position
automatically selects stations
stronger
than 35
dB/75ç,
(about
55pV).
(Stereo
distortion
factor
of 0.2%
or better) and the standard
position
selects
those
stations
stronger than
20
d7ll\
0
(about
10¡V).
(Stereo
distortion factor f rom 02%
to 1%).
These automatic
tuning
levels
can
be
adjusted
by
VR
101
for f ine
and
VR
1 02
for
standard
TR112
To
auto
button
I
I
I
-
t5
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