PINCH
ROLLER
T
R657
r--'
I ,
,
I
I
I
,
I
I
C
611'
I
, I
"659
t
122
Fig. 3-15 Tape-end
detect
circuit
19
Iy. When
0607
is
off,
capacitor
C61
0
is
charged
by
current
flowing
via path ® . When
0607
is
on, C610 discharges via path ® . Since the
time
constant
of
C610 and R631
is
much smaller
than
that
of
C610 and R656
(or
R657), the
charging
of
C610 proceeds
slowly
while
it
dis-
charges rapid Iy.
As
a
resu
It, the voltage at
'liJ
remains
below
+1.5
V while
0607
is
repeatedly
turned on and
off
.
When the tape reaches its end and stops running,
the counter
pulley
and the ring magnet stop
rotating.
At
this
time,
the
reed
switch stops
operating in
either
its on
or
off
position depend-
ing on where the ring magnet
has
stopped.
If
the reed switch
is
on, the
base
current
of
0607
stops
flowing
turning
it
off
, and
current
flowing
along path ® starts
to
charge C610
as
soon
as
U601
P LAY 12 R6 11
OUT
FAST 14 0 6
10
I STOP I
OUT
"6
06
2
STO
P
F
'N
IN L
693
C60 6 L _4_ME_MO
____
w...
_____
SO_L_EN_O_'D-,
"6
62
Q613
cu
rrent
from
path ® completes charging C609.
If
the reed switch
is
off,
0607
is
already
off
be-
cause
the
reed
switch
has
turned
off
and, there-
fore,
current
from
path ® continues
to
charge
C610.
When the voltage across C610 (voltage at ® )
exceeds
approximately
3
V,
base
current flows
through
transistor
0513
via path
(J),
thereby
turning
on
0613.
0613
turns
on
approximately
2.3 seconds
aher
0607
turns
off.
Since
0613
turning
on
is
equivalent
to
depressing the
stop
button,
the deck enters the stop mode.
When the deck enters the stop mode,
current
on
path
CD
or
(?)
stops
flowing
and
C610
dis-
charges via R656 and the fast solenoid and via
R657 and the pinch roller solenoid (current
flows
in the
direction
opposite
to
®
).
r-------------r-----
+3
9"
r-----
------
I
f--
-,--~-
+ 13"
CD
@
r-
--.-----j
_____
)
FLASHING
CIRCUIT
FLASHING
CIRCUIT
CD@
"
656
FAST
SOLENOID
C6
9 3
0
693
0695
T
L 6
91
A
REED
SW
I
TCH
S
693
---"'II
0607
+
R634
®
C609
:
@®
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