Technics ST-9038 Manual page 17

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
-