Service manual

7-
4
1 __ --------------DOUBLE-DENSITY DISK CONTROLLER
Integrated Circuits (Cont'd.)
u
I 3 4 5
7
SELECT IA
IB
IY
2A
2B 2Y
-----
OUTPUT
-----
OUTP:JT
INPUTS INPUTS
Vee
iO
2B
IDENTIFICATION
>
c
>
~
""
~
c: 0
~
+
c '"
c ~
> z
D
20
~
>
~
z
'"
INPUTS
INPUTS
OUTPUT
Vee
3Y
9
74123N
74LS157
WD1797·02
MAYBE
REPLACED
WITH
HE 443-90
HE 443·799
PART
NUMBER
HE 443·997
U14
U13
U12
COMPONENT
NUMBER
U15
HE 443-857
74LS367
u