Onkyo TX-L55 Service Manual page 39

IC BLOCK DIAGRAMS AND DESCRIPTIONS
74HCU04F (Hex Inverter)
1
1A
2
1Y
3
2A
4
2Y
3A 5
3Y 6
GND 7
(TOP VIEW)
TC74VHC541FT(Octal Bus Buffer)
1
G1
2
A1
A2 3
A3 4
5
A4
A5 6
A6 7
A7 8
A8 9
GND 10
TC7WU04FU (Buffer)
1A
1
3Y
2
2A
3
GND 4
14 Vcc
13 6A
12 6Y
5A
11
Truth table
5Y
10
A Y
4A
9
L H
4Y
8
H L
INPUTS
20 Vcc
19 G2
G2
G1
18 Y1
X
H
17
Y2
X H
16 Y3
L
L
15
Y4
L
L
14
Y5
X :Don't care
13
Y6
Z :High impedance
12
Y7
11
Y8
Vcc
8
1Y
7
Truth Table
3A
6
A Y
L
H
H L
2Y
5
TC74HCT7007A (Hex Buffer)
1A 1
1Y 2
3
2A
4
2Y
5
3A
6
3Y
7
GND
(TOP VIEW)
OUTPUT
An
X Z
X Z
H H
L L
TK15420(Operation Amplifier)
1
OUT A
-IN A 2
+
3
+IN A
4
VDD
TX-L55/LR552
Vcc
14
6A
13
6Y
12
11 5A
Truth table
5Y Y
10 A
L L
4A
9
H H
4Y
8
Vcc
8
7
OUT B
-IN B
6
+
+IN B
5