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PAUSE buttons are pressed, IC702 pin 2t is
changed to "L"
level, and the PAUSE indicator
lights up. And since pin 27 (LINE MUTE) of
this IC is changed to "H" Ievel, the signal circuit is
muted. If the REC and PAUSE buttons are both
pressed, IC102 pin 20 tnEel and pin Zf (FAUSB)
are changed to "L"
level, resulting in both the
REC and PAUSE indicators lighting up, and the
signal circuit being switched to recording circuit.
Furthermore, pin 27 is opened, permitting output
of the signal to LINE OUTPUT, but since pin 28
has been changed to "H" level, recording mute
mode is maintained.
o Timing Chart
7. Auto-stop Mode
A photo-interrupter
output is applied to pin
16 (END PAUSE) of IC102 during tape transport,
resulting in the capacitor connected to pin 17
(C312) being charged up and discharged repeated-
ly. The potential at pin 17 is thus kept below the
threshold voltage, and prevents activation of the
auto-stop mechanism.
When tape travel stops and the take-up reel stops
turning, the photo-interrupter output is no longer
applied to pin 16, and the potential on the ca-
pacitor connected to pin L7 (CgLz\ continues to
increase until it exceeds the threshold voltage.
The IC is thus switched to stop mode, thereby
stopping tape mechanisms.
Normal ooeration
\ Key input
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.-
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F i g . 3 - 4
P M 9 0 0 2 B t i m e c h a r t
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