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| TC-766-2
1C-766-2 |
16. REC MONITOR MUTE Circuit
5. With $607 ON, the signal comes out from LINE
sl04~2
-
(Refer to Fig. 18)
OUT only when the MONITOR
switch is set to
lee
di
i
'
as
ux
Q722
The
REC
MONITOR
MUTE
switch
(S607),
E
hd
located
on the rear panel, is turned ON
to prevent
With
the MONITOR
switch set to TAPE
position,
it
howling during recording.
when POWER switch is turned ON, LINE OUT signal
®
1.
This
circuit,
by turning OFF
Q507
of the
is muted to prevent a click noise.
That is because
ooo
1
Audio Amp section, cuts off the LINE OUT
Q722 is not turned ON for the period determined by
$s!
|
signal.
oe
a
es ie re sired Bo ny this
headphone
. 3
!
B+
:
.
:
P
perio
turns
and
accordingly
turns
amplifier
q
|
2,
During
OEsInGEY
DpERHOnp
ite
OBE
OFF to cut off LINE OUT circuit.
Since Q744 also
aie tL
is
q
because Q722 is ON.
turns
OFF,
B+ voltage
through
MONITOR
switch
oc
REC
coe
ae
ce
3. With the REC MONITOR MUTE switch (S607)
S104-2 coming from Q744 collector is ground
)
:@
set to the OFF
position, B+ turns ON Q507
through D769 and Q740 to prevent B+ from applying'
\
SS
@!
ray,
through S607, which activates relay (RY501)
to the Q507 base.
(Path @))
a A ine
ts
lone, f
and the LINE OUT signal comes out. (Path @)
oh
pecord mona
4. Also, in playback (Q744 is OFF) mode, Bt
a
t
goes through the TAPE side of the MONITOR
ey
1
switch
(S104-2)
to turn
ON
Q507
and
the
LINE OUT signal comes out.
(Path (@))
(When $104-2
is set to the SOURCE
position,
or when in record mode Q744 turns ON not to
aa
rear ane
supply B+, this circuit is cut off.)
qecelaveme eureaie Hoerell
Fig. 18
17.
Power Supply for Record
Bias Oscillator
oP
(Refer to Fig. 19)
.
@
SS
|. When the REC MODE switch (S103-1 or
.
ae
ae
§$303-1) is set to REC position, B+ is supplied
(REC MODE)
'
to the bias oscillator circuit.
(Path @)
4
4
2.
By pushing
the record (@) and forward (>)
OSC
pe
oe Oa
' C ouput (©) bee
ee @
pele nian
buttons, the base of Q745 is grounded.
unit
¢ ?
ee
Sea
ee
\
(Path @ )
ee)
— 12
0505;
J
4.
By 3., the flip-flop circuit consisting of Q744,
collector load resistance.
6.
With Q744 in the ON
state, the Q747 base is
grounded
through
D762,
Q744,
D761
and
Q719.
Q747
turns OFF and Q746 ON in the
SS
ae
Fig. 19
circuit operates.
(Path © )
—13—-
cae
mal
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