Technics ST-9038 Manual page 15

tt
PART
II
initial
state
(pin
@
"H",
pin
Ø
"L", pin@
ptn
)
@
changes
from
"H" fo "L",
causing pins
,,H
a
(9
to go
"H"
and pin
"'1",
@
remains
"H"
and
@
remains
"L',:.
d:
@
changes
from
"L"
to
"H",
but
@ and.
remaiir as
in b
and
c.
2-1-2
Start pulse
generation (differential circuit)
(The
above is an
example
of
start pulse
¡n
auto
tuning.)
When S3-3
is ín
auto
or
mono,
B
is
+B (þl)
via
R942 if the AT buton
is
not pushed.
W¡rh
the AT
button
pushed, one side of
Cg17
is
grounded'and
the potential
is
momentarily reduced
to
ground
(L).
But
it
is soon charged by the time constant of
R942
(10Ko) and
C917 (0.68¡lF),
and
irs
potential returnes
to
the +B line.
This can
be
f
igured
as
fo llows.
lf
the
AT
button
is
released
early
or
kept
depressed
longer
will not
change the
wave
form.
AT button
pushed
H
L
H
L
H
L
L
H
H H
ü
a
b
c
6
4
rogo
L
+B
Auto
Mono
----o
Pink
noise
s3-3
L
H
L
0
t(,
tc912
o
\f
o)
r
(o
o)
o
o)
(Ð
o)
tr
o)
o)
o
TR91
O
Þ920
tc912
5
5
down
A
uto-tu ning
(AT)
button
\ ;
By
of
time constant
C927
x
R942
-
13
-
RS
flip-flop
\t
o)
tr
c\l
\l
o)
tr
t'\
o)
O
+B
,'H,
"L"