UBI EasyCoder 501 – Service Manual
162
Parallel Interface Board 1-971704-41
22. PARALLEL INTERFACE BOARD, cont'd.
22.5
Circuit Diagram
1
/STROBE
2
74AC00
4
5
74AC00
C9
3
STROBE'
2
+5V
1
CLRBUSY
15
14
R1
74HC423
+5V
S3
6
&
STROBE
S2
IC8B
3
&
IC8A
74HC74
10
S
9
STROBE'
12
1D
11
>
C1
8
+5V
13
R
IC5B
C
R/C
13
/ACK
&
4
R
IC6A
74HC374
STROBE
11
CLK
RDDATA
1
OE
D7
13
D6
8
D5
14
D4
7
D3
17
D2
4
D1
18
D0
3
+5.3V
+5V
D1
C10
C4
C3
C2
C1
C5
C6
C7
11
10
C8
9
7
6
74HC423
C
R/C
5
&
12
R
IC6B
/ACK
IC1
AD7
D
AD0
2
AD6
D
AD1
19
AD5
D
AD2
5
AD4
D
AD3
16
AD3
D
AD4
6
AD2
D
AD5
15
AD1
D
AD6
9
AD0
D
AD7
12
WRSTAT
S1
R2
IC5A
R
1
/RESET
6
C1
>
3
1D
2
5
S
4
74HC74
DREADY
IC8D
12
&
11
13
+5V
74AC00
+5V
1
2
3
/STROBE
74AC374
11
CLK
1
OE
3
2
PE
D
18
19
/ERROR
D
4
5
ST1
D
17
16
ST2
D
7
6
ST3
D
14
15
SELECT
D
8
9
D
13
12
TESTID
D
IC2
BUSY
IC8C
9
&
8
ACK
10
74AC00
/SLCTIN
/INPRM
9
7
4
5
6
3
8
RN4
1
+5V
10
9
8
7
6
5
4
RN3
BUSY
F1
F2
F3
F4
F5
F6
F7
F8
F9
F10
F11
F12
F13
10 2
F14
F15
F16
F17
F18
+5V
R3
F19
F20
GNDC CONNECTED TO CHASSIS GROUND
( MOUNTING HOLES ON CONTACT )
P2
+5V
P1
1
19
2
20
3
21
4
22
5
23
6
24
7
25
8
26
9
27
16
28
P1
29
30
34
12
32
14
15
33
13
11
10
35
18
31
36
17
P1
37
38
ADBUS
GNDI
26
-12V
25
A1
24
+12V
23
A3
22
A2
21
A4
20
/RESET
19
GND
18
+5.3V
17
NMIHPC
16
X1
15
X0
14
RD
13
WR
12
XINT
11
CSX1
10
CSX0
9
AD0
8
AD7
7
AD1
6
AD6
5
AD2
4
AD5
3
AD3
2
AD4
1
P4
+5V
1
+5V
1
74HC367B
POLL
15
EN
12
14
IC7B
74HC367A
POLL
1
EN
/SLCTIN
10
/INPRM
6
TESTID
4
DREADY
2
IC7A
AD0
3
A4
AD1
5
CSX0
AD2
7
RD
AD3
9
A3
A2
A1
AD4
13
AD5
11
A4
CSX0
WR
10
AD7
9
A3
AD6
8
A2
AD5
7
A1
AD4
6
AD3
5
AD2
4
AD1
3
AD0
2
RN2
A1
2
A2
3
A3
4
A4
5
9
10
RD
6
WR
7
CSX0
8
RN1
74HC138
DX
1
15
WRSTAT
0
0
2
0
14
CLRBUSY
1
G
1
7
3
13
2
2
12
3
4
11
4
&
5
10
5
6
9
6
7
7
IC3
74HC138
DX
1
15
RDDATA
0
0
2
0
14
POLL
1
G
1
7
3
13
2
2
12
3
4
11
4
&
5
10
5
6
9
6
7
7
IC4