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a Counter reset
1. When the counter reset switch (S1101) is
placed ON, pin 41 of IC904 (PD6008) drops to
a low level, and pins 13 thru 18 go high, with
pin 19low.
2. Thus, when 51101 is held down, the tape
counter unconditionally resets the counter to
"0000".
However, real time operations by
IC904 continues, and when S1101 is released,
the counter will once again indicate real time.
Real Time Counter Function
When the Counter/Mode switch (S1102) is
placed ON, the counter can be switched to eigher
tape counter or real time counter operation.
1. Placing 51102 ON causes pin 40 of IC904
(PD6008) to drop low.
2. This causes a high output from pin 20 to turn
Q921 ON, illuminating
the LED1101 dot
indicator.
3. If the tape is traveling, voltage generated by the
right reel carrier Hall element (HA: H251) is
input to pins 5 and 6 of IC903 (NJM2903),
and output is obtained from pin 7.
4. At the same time, voltage generated by the Hall
element (HA : H253) of the left reel carrier is
applied to pins 2 and 3 of IC903, with output
from pin 1.
5. The outputs noted in 3 and 4 above are applied
to pins 30 and 31 of IC904 (PD6008) where
they are processed to obtain data on the
amount of tape time remaining. This data is
output from pins 13 thru 19, and 26 thru 29.
6. During the few second interval that data pro-
cessing is taking place in step 5 above, there is
no data present in IC904, and this causes the
output from pin 2O to vacillate between high
and low, switching Q921 ON and OFF causing
the dot indicator to blink. This reports initial
data acquisition.
7. During the time the dot indicator is blinking,
the numerical display will show preliminary
data, switching to an accurate display of the
calculation result a few seconds later.
8. As the processed data is stored in IC904, pin
20 will be locked high and Q921 will remain
ON keeping the dot indicator
illuminated.
This reports the fact that the counter is indicat-
ing real time.
9. Remaining tape time is continually processed
during tape travel to update the counter.
10. The unit indicated by the counter during the
PLAY mode is seconds.In the FAST mode, 10
second units are shown.
1l.If
during tape travel, the STOP or PAUSE
mode is entered. the counter will hold the
value at the point of entry.
l-2. When the tape reaches the "00.00" point on
the counter, the "00.00" display will be held
for approximately 30 seconds to account for
slight differences in tape length (even though
the tape may continue traveling).
o TAPE CAPACITY switch
The TAPE CAPACITY switch (S1018) is used to
allow for various tape lengths to be processed for
the tape time remaining display. Switching S1018
ON and OFF produces the logic levels at pins 38
and 39 of IC904 (PD6008) shown in Fig. 1-30.
Fig. 1-30 Tape capacity switch
o Tape travel direction indicator
LED indicators are provided so that the operator
can determine whether the tape is traveling in the
FWD or REV direction.
1. During the FWD mode of travel, the output
signal waveforms from pins 9 thru L2 otIC9O4
(PD6008) are as shown in Fig. 1-33.
2. These signals cycle through Q914 thru Q916,
turning them ON and OFF, thereby illuminat-
ing D1 thru D3 to indicate the forward direc-
tion of tape travel.
3. During the REV mode of travel, the output
signal waveforms from pins 9 thru
L2 of
IC904 (PD6008) are as shown in Fig. 1-34.
4. These signals cycle through Q914 thru Q916,
turning them ON and OFF, thereby illuminat-
ing D4 thru DG to indicate the reverse direction
of tape travel.
5. The blinking rate of D1 thru D6 is determined
by the mode the mechanism is in, and this
information is received through pins 33 thru 37
of IC904.
1 9
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