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7.6 CONTROL CIRCUIT
PLAY Operation
1.lVhen a cassette shell is loaded, the cassette shell
detection switch will go into the SHELL position
and the slack elimination circuit (Described
later) will commence functioning.
2. When the PLAY switch 'Sgoa is pressed on, the
voltage at Pin 17 of lCsor will become a High
level (Hereafter abbreviated to H level).
Cur-
rent from +Br will flow from the capstan motor
CM to Qszz. As a result, Qszz will become
conductive, and CM will start to rotate, At the
same time, current from *81 will flow through
Qszr, the reel motor RM, Rssr and Qsrz, ând
hence RM will also start or rotate.
3. The voltage at Pin 15 of lCsor will also become
an H level. Current from fBr will flow through
t h e p i n c h s o l e n o i d $ [ , r r o r , Q s r z 3 1 d Q s r r ,
hence SL r r o r will operate and the unit will go
into the PLAY mode.
REC Operation
1. When a cassette shell having erasure prevention
tabs is loaded (The erasure prevention switch
Srros will go into the NO HOLE position), the
PLAY switch Sgos and the REC switch Ssoc
will go on simultaneously. The operation of the
pinch solenoid Srror and the capstan motor
CM is the same as for "PLAY operation".
2. The voltage on Pin 16 of ICsor becomes H level.
As base current flows from Rsoe, Rtro to Qtos,
Qo og becomes conductive, the bias oscillator
circuit operates and the unit goes into the REC
mode.
When a cassette shell which does not have erasure
prevention tabs is loaded (Srros goes into the
HOLE position), Pin 5 of ICsor will become
Low level (Hereafter called L level), regardless
of the position of Ssoa, and hence the unit will
go into the REC mode.
FF, REW Operation
1.When the FF switch Ssoz is turned on,Pin22
of ICso r will become H level. Cunent from *Br
will flow through Qszr, the reel motor RM and
Qs r o, and thus RM will start to rotate.
2. Current from *Br will flow through the brake
s o l e n o i d S L r r o u , R s l s a n d Q s r e , h e n c e S L r r o z
will operate and the brake will be removed.
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3. The REW operation is basically the same as the
FF operation except that the polarity of the
voltage supplied to RM is reversed.
PAUSE Operation
1. As previously explained, when the unit is in
either the PLAY or REC modes, current from
*Br flows into the pinch solenoid SLrror, the
capstan motor CM, the reel motor RM and the
bias oscillator circuit.
2. If now the PAUSE switch is pushed on, Pin 15
of ICsor will become L level. As a result,
Slrror will not operate and RM will notrotate
(Refer to section entitled "PLAY operation").
Hence the PLAY or REC condition will be
temporarily removed.
TIMER START Operation
r PLAY Operation
1. Press the TIMER START PLAY switch Saor-s
on, and then put the POWER switch on using
the timer etc. While Carz is charging up, Pin 4
of ICsor will become L level. and thus the unit
will operate in the same ïyay as if the PLAY
switch S4o3 ïyere put on.
2. When the power supply voltage reaches its final
value (after about 4 seconds), Pin 14 of lCsor
will become H level, and the unit will go into
the PLAY mode.
. REC/PLAY Operation
1. Press the TIMER START PLAY switch Ssor-e
on, and then put the POWER switch on using
the timer etc. While Car r and Carz are charging
up, Pins 4 and 5 of ICsor will become L level,
and thus the unit will operate in the same ïyay
as if the PLAY switch Ssos and the REC switch
Ssoa were put on simultaneously.
2. In the same u/ay as for PLAY operation, Pin 14
of ICsor becomes H level, whereupon the unit
commences REC/PLAY operation.
MEMORY STOP Operation
Press the MEMORY STOP switch on, and then
press the REW switch on. When the tape counter
indication reaches "999",
the REW operation
will stop.
1. Press the MEMORY STOP switch Saor-r on, and
press the REW switch Sgor on. lVhen the tape
counter indication reaches "999", a pulse will be
sent from the microcomputer (ICaoe ).
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