Service manual

1526 AND 4023 CIRCUIT THEORY
R56
1.15
2.2 "H
V1 .. MHz
l..r----?": --0-1-- '~: -~
- , .
L _ ___ "
R55
C34
.04~
" .,
"I'"
o C!
11 8 U10C
D-
74
-
00
--......::..j 74177
1 MEG HZ
9
117
R57
7400 7400
7
47
Clock Circuit
Crystal Y 1 generates the fundamental 4 MHz clock. The circuit illustrated below the crystal stabilizes
and squares
the signal. U 1 OC divides the input frequency by 4. A 1 MHz clock is output on pin 9
of U 1 OC. This is the processor system clock.
9