Integra DTR-7.6 Service Manual page 114

IC BLOCK DIAGRAMS AND DESCRIPTIONS
74HC04F(Hex Inverter)
1
1A
2
1Y
3
2A
4
2Y
5
3A
6
3Y
7
GND
TC74VHC541FT/T541AFT(Octal buss buffer)
1
G1
2
A1
3
A2
4
A3
5
A4
6
A5
7
A6
8
A7
9
A8
10
GND
TC74VHC157FT(Quad 2-channel Multiplexer)
SELECT 1
14 Vcc
1A 2
13 6A
3
1B
4
1Y
12 6Y
5
2A
11 5A
2B 6
10 5Y
2Y 7
9 4A
8
GND
8 4Y
Vcc
20
Truth Table
G2
19
INPUTS
Y1
18
G2
G1
Y2
17
X
H
Y3
16
X H
Y4
15
L
L
Y5
14
L
Y6 L
13
Y7
12
X:Don't care
Y8
Z:High Impedance
11
Vcc
16
ST
ST
A S G
15
4A
B A
14
4B
Y
B 13
4Y
A
Y 12
3A
B
A 11
3B
10
Y Y B
3Y
9
TC7WU04FU(3 Inverter)
OUTPUT
An Yn
X
Z
X
Z
H H GND
L
L
DTR-7.6
Truth Table
INPUTS
OUTPUT
SELECT A B
H X X X L
L L L X L
L L H X H
L H X L L
L H X H H
X:Don't care
1A 8 Vcc
1
3Y 7 1Y
2
6 3A
2A 3
5 2Y
4