Hitachi D-E99 Service Manual page 16

)-E99
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IC PIN FUNCTION TABLE
1. IC401 (HD44801 A35 for mechanism/ ATRS control)
Pin
I
No.
Pin Symbol
Function
•
1 BIAS
• Control output pin to operate the bias oscillation circuit. Outputs Lo potential normally
and Hi potential in the REC mode and the REC-PAUSE mode after recording. Outputs
after elapse of the inhibit time of 120 ms when the mode is changed from STOP, PLAY or
PAUSE, and outputs after elapse of the inhibit time of 820 ms when the mode is changed
from FF or REW.
2
TAPE SELECT 1 • Tape select switch (S2) position detection input pin. Detects the tape select switch
3
TAPE SELECT 2
position according
to
the truth table shown below and changes over the output data.
I
~n
NORMAL FeCr Cr02 METAL
I
s
Pin(V
0
1
0 1
Pin@
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0 0 1 1
4
TEST START • ATRS test start detection input pin. Inputs Hi potential normally and inputs Lo potential
by the button operation in the REC, REC-PAUSE or REC-HOLD mode,
to
detect the
ATRS test start. The ATRS test starts actually when the input is detected during the
REC or REC-PAUSE mode.
• Outputs Lo potential when executing the ATRS test and outputs Hi potential normally.
5 TEST INDI.
· Test indicator drive output pin. Outputs Lo potential normally and outputs the flashing
pulse with 1.28 sec. period when executing the ATRS test. When error occurs during
(
the ATRS test, the flashing pulse with 160 ms period is output as error indication.
This error indication continues until the play button or pause button key input is given.
l
I
I
I
J1IU1illlJ1JUUl
! I
I
-H
~-Borns
I
--1 640ms
r-
1
i
1.28s
I
--i
f---160nis
••
6
AFOSC
• AF signal oscillator control output pin. Outputs Hi potential until ATRS test starts when
(1 kHz/12 kHz)
I
power is ON, and outputs Lo potential when recording the 12 kHz signal during execution
I
of the ATRS test. It is set to the Lo potential output mode after A TRS test is completed.
"-
7
A/D COMP.
i
· A/D comparator output input pin.
I
Detects the inversion output (fall signal from Hi to Lo potential) of the A/D comparator
during execution of the ATRS test.
- - -
8
A/D RESET
• A/D comparator circuit reset control output pin.
Outputs Lo potential in other modes than the ATRS operation, and outputs Hi potential
with 80 ms width for approx. 3 sec. after power is supplied or just after scanning the A/D
comparison reference voltage during execution of the ATRS test to reset the test sample
hold.
9
A/D SELECT
I
· A/D comparison circuit input (play output signal) channel select control output pin.
When Hi potential is output : R channel
When Lo potential is output : L channel
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