Akai GX-77 Service Manual page 25

(cl
(Mi-com}
|
®,
\
|
it
|
©! -
0 T
reel
Wit
@9 vo
@) 01
@2 02
©o3
@oe
@os
(@) 06
©o- 0O- 0 -0- 0-0-0 -
. =
fy
uy
i;
LED cames on when the pulse is of "H" level
1
©
Se ee
ee
<—Disploy of the 3rd digit
)
~<e—Disploy of the 2nd digit
|
!
t mM J
[ ] v1
<— Display of the
ist (rightmost) digit
°
|
~=<—The pulse for turning on each
tunction mode indicotor
~<—Segment o and PAUSE IND
<—Segment band REC IND
"—Segment c and FWO IND
<—Segment d and REV IND
~<—Segment e
<—Segment t
~<— Segment g
Oisploy of the ist (rigntmost) digit
Display of the 2nd digit
Display of tne 3ra aigit
Disploy of the 4th (leftmost) digit
Activation of each function mode indicator
Also the function mode indicators are lighted up
by the operation timing of the control signal from
the microcomputer. Here, we take the example of
FWD PLAY/PAUSE in Fig. 29. FWD PLAY shall
be called simply as PLAY hereinafter. In PLAY/
PAUSE mode, the function mode indicator,
PAUSE is always lighted and PLAY is flashing.
Firstly look at the longitudinal raw of the function
mode indicators of DO ~ D3 in Fig. 29.
You will see that PAUSE IND is "H" level, PLAY
IND is "L/H" flashing and others are "L" level.
(DO ~ D3) and IC1 © signals are inputted into
the latch circuits of @, @, @, @ and © of
Fig. 29
IC2 in Fig. 27.
The latch circuit is shown in Fig. 28, and in such
case, since IC2 ©) polarity is always "H"', data is
always "H", data is outputted when the clock is
*"*H"', and when it is "'L'', the data latched and held
is outputted.
Therefore, in FWD PLAY/PAUSE, when the clock
signal of IC1 @ is "H", the PAUSE indicator is
"H" and FWD IND is "L/H"' flashing, and "H"
signal appears in IC2 @) in Fig. 27 to turn TR13
ON and flashes PAUSE IND, and in IC2 @),
"L/H" flashing signal appears to turn TRI1 ON
and OFF and flashes FWD IND.
25