Audio Block Diagram ( B )
HG454BLA
1-7-4
REC
AMP
100
3
AU
T
O
BIAS
2
1
+5V
+5V
Q401
Q406
BIAS
OSC
Q402
N-A-PB
T
O
Hi-Fi
A
UDIO BLOCK
N-A-REC
Q405
(PB=ON)
Q403
5
EQ
AMP
9
8
7
LINE
AMP
REC-ON
A
UDIO HD-SW
CONTR
O
L
MUTE
11
6
PB-ON
SP/LP-ON
P
TUNER
IN2
IN1
R
ALC
DET
ALC
IC301
(A
UDIO SIGNAL PR
OCESS)
15
13
17
3
A-PB/REC
CN504
4
A-COM
6
AE-H
5
AE-H/FE-H
A
UDIO
HEAD
A
UDIO
ERASE
HEAD
A
C
HEAD ASSEMBL
Y
FE HEAD
2
FE-H
1
FE-H-GND
CN501
MAIN CB
A
PB-AUDIO SIGNAL
REC-AUDIO SIGNAL
Mode : SP/REC
71
A-MUTE-H
IIC-B
US SCL
IIC-B
US SD
A
T
O
SER
V
O/SYSTEM
CONTR
OL BLOCK
FULL
ERASE
HEAD
68
69
SERIAL
DECODER
(DECK ASSEMBLY)
12
16
INV
AT
T
Comparison Char
t of
Models & Marks
Model
Mark
29B-250
29B-750
A
B