Yamaha GX-900 Service Manual page 77

A B
SCHEMATIC DIAGRAM (OPERATION)
1
µ
IC810 : PC4570HA
2
Dual OP-Amp
1 2
– + + –
1 2 3 4 5 6 7 8 9
V V –Vm +Vm V +Vm –Vm V V
CC O1 1 1 EE 2 2 O2 CC
IC814 : YSS247-D
YMERSION
3
11 8 3 2 1
AVDD
14
FILTER
+1
VREF 17 VREF
SWITCH –1 SWITCH
YMERSION
TO SWITCHES
SWITCH –1 SWITCH
SW 13
4
+1
COMPARATORS
FILTER
AVSS 15
12 10 7 6 5
5
6
7
8
C D E
0
4.9
4.9
MUTING
0
-6.0
0
0
-6.0
0
5.0 12.4
0
0
9 12.1
7
8
0 6
0
4
2
0
24 23 22 3 0
0 5
-11.8
SWITCH
BUFFER
+1
TONE CONTROL
+1
SWITCH
20 19 18
YMERSION
P87
G-9
F G
P87
H-2
5.5 5.5
4.9
5.0
5.3 5.3
0 0
0.9
0 0
0
0
0
0.6 3.3
0
4.5
4.5
5.3
5.5
0
H I J
-24.8
-24.8
-24.8
-26.8
-21.4
P87
H-9
IC815 : M66004MASP
FL Driver
DISPLAY CODE
CS 14 SERIAL
REGISTER CGROM
SCK 15 RECEIVE 59 SEG00
(8BITx16) (35BITx160)
SDATA CIRCUIT
16
CODE SEGMENT 33 SEG26
WRITE OUTPUT
31 SEG27
CIRCUIT
CGRAM SEG35
23
(35BITx16)
CORD/
COMMAND
RAM
CONTROL
WRITE
CIRCUIT
18 P0
OUTPUT
PORT
(2BIT)
17 P1
DISPLAY
CONTROL
RESET 13
REGISTER CODE
* All voltage are measured with a 10MΩ/V DC electric volt meter.
SELECT
12 DIG00 * Components having special characteristics are marked Z and
XIN 21
CLOCK DISPLAY DIGITAL
1 DIG11 must be replaced with parts having specifications equal to those
GENERATOR CONTROLLER OUTPUT
XOUT 20 64 DIG12
CIRCUIT originally installed.
61 DIG15
* Schematic diagram is subject to change without notice.
K
GX-900
FL
DRIVER
88