NAD T 741 - Audio Board U302: TC9273 N-004 Block Diagram; Digital Board U761: 74 HCT00 Block Diagram; Key Board U201: LC87 F65 C8 A Block Diagram

47
2S1
1
V
SS
26
V
DD
27 S1
3S2 26 S2
4S3 25 S3
5S4 24 S4
6S5 23 S5
7S6 22 S6
8S7 21 S7
9S8 20 S8
10S9 19 S9
11S10 18 S10
12S11
13
GND
14
CK
15
DATA
16
RESISTER
17 S11
(L-ch)
10bit
Latch
Circuit
LEVEL SHIFT + SHIFT RESISTER
CIRCUIT
(R-ch)
10bit
Latch
Circuit
(Same
as L-ch
Circuit)
AUDIO BOARD
U302: TC9273N-004
DIGITAL BOARD
U761: 74HCT00
11A
21B
31Y
42A
52B
62Y
7GND
14 V
CC
13 4B
12 4A
11 4Y
10 3B
93A
3Y8
Interrupt Control
IR
Flash ROM
PC
ACC
B Register
C Register
PSW
RAR
RAM
Stack Pointer
Watch Dog Timer
ALU
PLA
Stand-by Control
CF
Clock
Generator
RC
X'tal
Bus Interface
Port 0S100 Port 1S101 Port 3Timer 0
Port 7Timer 1 Port 8Base Timer
ADCVFD Controller
Weak Signal Detector
INTO-3 Noise rejection Filter
KEY BOARD
U201: LC87F65C8A