Yamaha YST-SW320, Service Manual

Page: 15 / 23

A B C D E F G H
1
2
3
4
5
6
I J K
7
8
YST-SW320
■
SCHEMATIC DIAGRAM
V
O1
2
–Vm
1
3
+Vm
1
4
V
EE
5
+Vm
2
6
–Vm
2
7
V
O2
8
V
CC
9
V
CC
1
1
– + – +
2
IC1, 4, 7—9 :
µ
PC4570HA
Dual OP-Amp
IC5 : M51848L
CR Timer
* All voltage are measured with a 10M
Ω
/V DC electric volt meter.
* Components having special characteristics are marked
Z
and
must be replaced with parts having specifications equal to those
originally installed.
* Schematic diagram is subject to change without notice.
2SK304 (E, T)
NJM4558L
µ
PC1237HA
M51848L
µ
PC4570HA
1
9
1SS133
S2L20U
1SR139-400
MTZJ3.6B
MTZJ12.0C
MTZJ24.0B
Anode
Cathode
B
C
E
2SA970 (GR, BL)
2SA1015 (Y)
2SA1145 (O, Y)
2SC1815 (Y, GR)
2SC2240 (GR, BL)
2SC2705 (O, Y)
2SC2878 (A, B) RBV-602
D
G
S
2SA1492Z (O, P, Y)
2SC3856Z (O, P, Y)
2SC4688 (R, O)
PIN CONNECTION DIAGRAM OF TRANSISTORS, DIODES AND ICS.
14
L.P.F.
L.P.F.
L.P.F.
H.P.F.
B.P.F.
LIMITER
PRE DRIVE
POWER DRIVE
PS AMP
PROTECTION
POWER SUPPLY
A.N.I.C
POWER SUPPLY
SUB
POWER SUPPLY
AUTO POWER ON/OFF
CIRCUIT
0
0
0
11.8
3.4
3.4
2.7
5.9
-0.1
0
0
0.6
0
0
-0.1
0
0
0
-11.9
0
0
0
-11.9
0
0
0
11.8
0
0 1.8
0
0
0.6
7.9
7.3
0
0
0
-11.9
0
0
0
11.8
AC 97.6V
AC 25.9V
AC 11.2V
0
11.5
5.6
5.6
11.5
0.9
0
0.7
11.5
0
7.9
0
3.9
7.9
6.7
0
3.9
6.6
1.3
0
0
7.5
0
1.3 6.6 7.9 5.3 7.5 7.5 7.9
0
0
-16.4
16.4
0
16.4
11.8
0
-16.4
-11.9
6.6
6.0
0
0
0
11.8
0
0
-0.3
-0.3
-11.9
0
0
0
0
-11.9
0
0
0
0
11.8
0
0
-1.5
0 0 0
0
0.1
0.1 0.1
-11.9
11.8
0
0
0
0
0 0
-62.5
-61.9
-61.8
-61.9
-62.5
-61.4
-61.8
-61.4
-1.6
-61.4
-61.8 -61.8
0
0.2
0.7
0.7
61.6
62.1
62.9
62.4
61.6 61.6
62.1
1.7
-1.0
-1.6
1.7
1.7
1.1
4.2
63.1
63.1
3.6
1.1
3.6
0.6
0.6
2.6
3.2
62.6
0
63.1
63.0
62.6
62.7 62.7
63.1
62.4
63.1
2.6
2.6
63.1
0
0
63.1
62.4
62.4
0
0
0
-2.7
-62.3
-3.2
-0.5
-0.5
-1.0
-62.8
-3.6
-3.6
-1.0
-4.2
-62.8
-1.6
-62.8
-62.3
-62.9
-63.4
-62.8
62.8
-63.1
-63.4
-62.8
-2.6
-2.6
-2.7
0
-62.8
3.3
0
0.7
0
2.0
0 0 0
6.6
6.0
0.7
24.3
63.1
0
0
-62.8
4.2
IDLING CURRENT ADJ.
DC 50mV to 250mV
A
B
+
–
B
CE
2SA1837
2SC4793
1
8
IC11 : NJM4558L
Dual OP-Amp
–
IN
1
2
+IN
1
3
–
V
CC
4
+IN
2
5
–
IN
2
6
OUT
2
7
+V
CC
8
OUT
1
1
–
+
–
+
IC3 :
µ
PC1237HA
Protector IC for Power Amplifier
1
2
5 3 4
7 8
6
Overload
detect
Mid-point
potential
detect
Flip flop
circuit
Vcc on
mute
AC OFF
detect
Latch / automatic
return select
Relay
drive
circuit
GND
Vcc
GND
6
4
1
2 3
TRIGGER
OUT
RESET
REFERENCE
VOL
T
AGE
THRESHOLD
DISCHARGE
VCC
7
8
+
–
FLIP-
FLOP
+
–
5
R R R
S1NB20
+
–
2SC1846S
E C
B
1
2 3
1:OUTPUT
2:COMMON
3:INPUT
NJM78L08A
B
C
E
NJM78M12FA NJM79M12FA
1: OUTPUT
2: COMMON
3: INPUT
3 2
1
1:COMMON
2:INPUT
3:OUTPUT
3 2
1