Technics ST-9030 - Dial Cord Installation Guide; L.C. Tuning Muting Band Switch Circuit; Muting NAND Circuit

'Ì"'
@
L.C.tuning rnutlng
band
s'witch
circuit
,Although the
muting
circuit
is composed
of
the mu-
ting band
switch
circuit
and
SIN
level switch
c¡rcuit,
it is
so
arranged
as
to apply
the
narrow
band signal
from
the narrow
lF circuit
10
TR418 of
Fig. 6
for
providìng
a
more
perfect
muting
circuit,
taking
malfunction
arising
from
neigboring
stations
into
consideration,
When
ihis
signal
level
exceeds
0.6V,
TR418
is turned
"ON", w¡th the
base of TR410
reduced to
ground
poiential,
and
thus TR410
is
turned
"OFF".
ren the
remains
3N"
of
emitter
F"
,
and
:harged
tage
ap-
reaches
tht
¡nto
reverse
n olher
¡es
-Af
Í
Fie.4
*.Af of
l state,
circuiT
fhe lF
liecj
to
rg
of
;tAte.
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ì
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ú
4
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ì:
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l'ññ"Li-l
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@
füuting NAND circuit
'
.
.
'
TR410 in
Fig. 6
performs
NAND
switching function. The
3
kinds of
lignals
as
explained
in
the earlier
mentionecl items
1,
2 ano
3 are appli-
ed to the base
of TR41O.
The
respective signal
levels
are
all
rendered
to
'bà
0V;
and
TR41O
is turnèd
"OFF"
only
when these ar:e
simultaneous-
ly
applied to TH410
(hatched
portion
in Fig. 7). Accoidinglv,
positive
potential
is deVeloped
at
the collector,
which
voltage iS
transmitted
to
ihe
relay cjrive circÛit
(at
the
same time, transmittedito
the lF band
swítching circuit
from the
muting switch
circu¡t) to opefate.the
relay
to
provide
the set
output.
Should
even
one
of
the 3
kilds of
the inptrt
signals to
TR410
is of
posítive
potentíal,
TR4'10
is turhed
"OÌ'J",with
the collector
reduced to
ground
potent¡al,
and
thus the
r:elay ¡s
not
ôperated.
(
ffi
ÐIAL
CORD IT{STALLÅTION
GU¡DË
JLIL
.To íeby
diive
c¡rcúit
(f\4UTING
NAND
CI RCUIT)
l-lg.
þ
MUTING
FUNCTIONING
RANGE
¡F5
lnput
o
.:,:,]
{SIGNAL
APPLIED
TO
NANÐ
CIRCUIT)
Fis.7
S/N
5/N
I
I
I
i
I
@
0v
IF.V
o
OV
l-1"-*ii.-"--:j
lrc203tr
r¿rab,ll
*1=1,/
.o
-sl¡r.
o
For
threading
a
fresh
cord,
proceed
as
follws.
1. Prepare a
fresh
cord
rnore than
18}cÍtçO:7å'\in
length.
2.
Bring
the variable
capacitor
into
a state
where
the drum
is
completely
turned
to
the
right
(maximum
capacity
and
lowest
freguency
for the
variable
capacitor).
3. Direct the
cord
in the
order
from 1
to
7.
4. Stretch
the
cord
in such
a.tension
as the
spring
length is
elongated
by
1.5 times
that
of the
original
stale.
5.
Fix
the
knot of
thecord
with
the
bond.
E
sr-gogo
'
i
ri
J:.i'
:
...
2
5
\
lnput level
tr)
T-e030
E
pcinter
Tuning
-1