Yamaha YSP-900 Service Manual page 60

A B C
YSP-900
INPUT 2/2
1
2
3
4
5
POWER CABLE
~
6
0
2.8
2.8
AC 4.8
10.3
10.3
7
8
9
10
# All voltages are measured with a 10MΩ/V DC electronic volt meter.
# Components having special characteristics are marked s and must be replaced
with parts having specifications equal to those originally installed.
# Schematic diagram is subject to change without notice.
60
D E F
Safety measures
• Some internal parts in this product contain high voltages and are dangerous. Be sure to take safety measures during servicing, such as wearing insulating gloves.
• Note that C523 is dangerous even after the power is turned off because an electric charge remains and a high voltage continues to exist there.
Before starting any repair work, perform discharge by connecting a discharge resistor (5 k-ohms/10 W) between C523 terminals.
安全対策
・この製品の内部には高電圧部分があり危険です。修理の際は、絶縁性の手袋を使用するなどの安全対策を行ってください。
・C523には電源をOFFにした後も電荷が残り、高電圧が維持されており危険です。
修理作業前に放電用抵抗 （5 kΩ/10 W） をC523の端子間に接続して放電してください。
5 k-ohms
10 W
SWITCHING
113.2
POWER SUPPLY
0 332.4 33.2
453.5
112.3
331.8
331.8
1.0
0
1.0
0.1
0
0
0.1 0
0.1 0.1
0.1 3.9
0.1 1.5 0.1 15.1
15.1 0
0 0.1
15.1
0
1.3 0
2
3.3
~ ~
~
~
3.1
~
~ 3.2
~
3.3
0
~ ~ 0 3.1
0
~
0
0
0
~ 3.1
~ 0 0
0
0 0
~ ~
~ 10.3
~ ~ ~
~ 0
~ ~
0
~ 0 0
~ ~ RESET
CIRCUIT
~
~ 0
1.0 1.0
0.8
0
~
0.1
0.1
G H
0
5.1
0
5.1
5.1 10.1
0
15.2 15.2 10.9
15.2 10.9
0
0
0
0
7.7 5.0
10.1
7.7 5.0
0
0
1
B-1
-25.8
0 -26.4 -24.8
10.3 4.0 4.0 3.3
4.0
10.3 4.0 3.3
ISS355
0
IC509: NJM78M05FA
IC510: NJM78M12FA
Voltage regulator
I J K
Page 58 L4
to AMP_CB708
Page 59 G4
POINT B-1 P.C.B. INPUT
to INPUT(2)_CB4
① C531(+)
② Q504(C)
3.3
4.9
0
Page 59 G6
to INPUT(3)_CB901
Page 57 J6
to DSP_CB10
INPUT(1)
IC502: TC4013BP
Dual D-type flip flop
RESET1 4
INPUT
SET1 6 1
Q1
DATA1 5
2 Q1
CL
CL
OUTPUT
CL
CL
CLOCK1 3 CL
CL
RESET2 10
COMMON SET2 8
13 Q2
DATA2 9
12 Q2
CL CL
CL
CL
CLOCK2 11
CL
CL
VSS 7
14
VDD
L M N
AC cable AC cable AC cable ON
ON OFF
IC507: NJM431
Adjustable precision shunt reglator
A K
ANODE CATHODE
R
REFERENCE
IC506: AN77L04
Low dropout voltage regulator
Input Short Circuit
Protection
Over Current
Protection
Error Amp.
Rush Current
+ Protection
-
Thermal
Protection
1 3 2
IN GND OUT
IC505: FA3641N
PWM control IC
CS VCC
8 6
0.82V~0.68V 15.5V
6.5uA
REF 7 5V VCC +
5V REF
– 0.9mA
UVL0
EMB
15.5V +
+
– + –
0.8V
– 16.5V/9V
8.5V~7.9V
3.0V
+ EMB
4V 5 OUT
OUTPUT
–
FB 2
–
–
– PWM
Dmax
+
70%
OSC
RM RT R
QB 4 GND
0.24V FF
Q
+
– S
–
+
1 3
RT IS+