Yamaha GX-505 Service Manual page 49

A B C
SCHEMATIC DIAGRAM (GX-505 CD)
1
2
3
4.3
1.8
4
ACT
MOTOR
DRIVE
0
5
0
5.6
2.4 2.4
2.4 2.4
2.1 2.5
0
0 2.7
0 0
0 0
0 0
2.5 ~
2.5 ~
2.4
5.6 5.6
5.6
6
0
4.8
0
7
8
MOTOR DRIVE
9
10
D E F
CD HEAD AMP
3.7
2.4
2.4
1.3
2.4
1.9
4.8
0
SPC & DAC
0
0
2.4
2.4
2.3
4.8
5.6
2.4
5.6
q
2.4
2.4
2.4
1.3
2.4
4.0
0
6.0 0
0
G H I
4.8 5.5
REGULATOR
REGULATOR
4.9 8.0
5.6 10.8
7.3
1.7
6.2
1.2
0 1.2
0 1.2 7.3
6.2
0
2.7
0 0
0
0
4.8
14
4.8 4.8
11 12
13 4.8
0
14
4.8
11 0
4.8 10
10
~ 9 4.8
8
4.8
10
0 9 ~
11
0 4.8
8 9
0
1 7
~ 0
2 3 ~
7
0
4.3
4.8
0
~
4.8
0
0
0
0
4.8
~ 4.9
~
2.4
0
2.4
2.4
2.4
4.8
0
w
0
4.1
0
4.3 0
0
CD CPU
0
2.1 0
2.3 0
0 4.8
0 0
0 0 0
0 0
0 0
0 0
0 0
0 0
4.8 0
0 0
0 0
12.2
8
0 2
0 0 3
0 3
1
0 2
LPF
0 6
0 5
0 0 5
0 6
7
4.8 4
-12.1
0
0
J K
MAIN(1)
P68
A-2
6.2
0
0
INPUT(1)
P64
INPUT(3)
Point q (Pin59 of IC5)
V : 2V/div
DC range
0V
Point w (Pin39 of IC8)
V : 2V/div
DC range
0V
0 4.8
1 2
4.8 5 6 3 4
4.8
0
CD(Lch)
12.2
MUTING
8
0
1
-12.0
0
4.8
4.8
0
-12.0
0
0
-12.0
0
7
4
-12.1
L M N
GX-505/GX-505VCD
IC4 : AN8806SB
Digital Servo Head Amp
6 7 29 27 28 8 9 10 17 11 12 19
+
+
RF
EQ AGC
DETECT
VCBA
PDAC
36 +
+
ENV DETECT
C.SBDO
BDO 13
14 BDO
VCBA
PDBD 15 C.SBRT
35 OFTR
+
+ +
16 OFTR
+
20 VREF
PDFR 31
VCBA
PDF 34
+ 5 VCC
+
+
18 GND
VCBA
+
PDER
32 21 LD OFF
A-9
+
+ + 2 LD
PDE 33 +
+
+
30 24 25 26 23 22 1 4 3
P64
IC1 : M56748FP
C-8
4 Channel BTL Driver
STAND
TSD
BY
OP1
VREF-IN 1 36 STAND BY
VREF-OUT 2 35 SS. GND
N. C. 3 34 STAND BY
OP1 OP1
GAIN 1 4 33 GAIN 4
10K 10K 10K 10K
VCTL 1 (–) 5 32 VCTL 4 (–)
VM 1 (–) 6 31 VM 4 (–)
PA PA
VM 1 (+) 7 30 VM 4 (+)
PA
PA
8 29
9 28
GND GND
10 27
11 26
PA PA
VM 2 (+) 12 25 VM 3 (+)
PA PA
VM 2 (–) 13 24 VM 3 (–)
10K 10K
VCTL 2 (–) 14 23 VCTL 3 (OUT)
OP1 OP1
GAIN 2 15 22 VCTL 3 (–)
N. C. 16 21 VCTL 3 (+)
OP1 VCC
10K
VCC 17 20 VCC
OP1
REG 5V 18 19 REGBASE
10.8K 3.6K
IC9 : TC74HC125AF
Quad 3 State Bus Buffers
1C 1 14 Vcc
1A 2 13 4C
3
1Y 12 4A
2C 4 11 4Y
2A 5 10 3C
2Y 6 9 3A
GND 7 8 3Y
IC10 : TC74HC04AF
Hex Inverters
H : 50 nsec/div
1A 1 14 V DD
1 : 1 probe
1Y 2 13 6A
2A 3 12 6Y
2Y 4 11 5A
3A 5 10 5Y
3Y 6 9 4A
V 7 8 4Y
SS
µ
IC13, 14 : PC4570G2
Dual OP-Amp
OUT 1 1 8 +V CC
H : 0.1 µsec/div
–IN 2 7 OUT
1 2
1 : 1 probe + – + –
+IN 3 6 –IN
1 2
–V CC 4 5 +IN 2
IC2, 3 : TA8409S
Full Bridge Motor Driver
VCC VS
2 6
VREF
STAND-BY 8 VREF
CIRCUIT
CIRCUIT
IN 1 9
7 OUT 1
3 OUT 2
IN 2 1
THERMAL
SHUTDOWN
CIRCUIT
5
GND
* 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.
62