Yamaha CDR-HD1500 Service Manual page 49

A B
1
I SCHEMATIC DIAGRAM (OSD)
2
U, J models only
OSD (2)
3
4
5
6
7
C D
RS-232C DRIVER/RECEIVER
5.0 5.1 5.1 5.0 0 -8.1 0 5.0
24 8.8 -2.4 4.8 -4.2 -8.1 -8.1 0
ON SCREEN DISPLAY CONTROLLER
0 4.9
2.3 5.1
2.4 4.9
0 0
0 4.9
2.3
2.4
0.1 2.0
5.1 4.9
5.1 0
0
4.9
4.9 1.7 1.7
1.0
1.0 1.0
1.7
3.8 3.8
3.2
# All voltage are measured with a 10MΩ/V DC electric 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.
E F G
0
-8.1
0
0
4.7
0
-0.6
4.7
1.0
0.4
4.7
1.0
0.4
OSD (1)
IC900: SP232ECP
RS232 Driver/Receiver
T1O T2O R1I R2I
13 8 13 8
T1 T2
Charge
Pump
R1 R2
15 12 9 12 9
GND T1I T2I R1O R2O
H I
x :NOT USED
O :USED / APPLICABLE
PIN CONNECTION DIAGRAM OF TRANSISTORS,
DIODES AND ICS.
2SA1037 1SS355
2SC2412K MA732
2SD1938F MA8051-M
Anode
C
E
B
Cathode
SP232ECP LC74781-9844
12
8
16
24
1 1
IC950: LC74781-9844
On Screen Display Controller
9
CS
8-bits
Serial
latch
SIN 11 +
parallel command
converter decoder
Horizontal Vertical Horizontal Vertical Blinking
SCLK 10
character character display display and inversion
size size position position control
register register register register register
RST 23 Blinking
Horizontal Vertical Horizontal Vertical
and inversion
size size dot dot
control
counter counter counter counter
circuit
VDD1 24
Blinking Blinking
and inversion and inversion
VSS1 1
control control
register register
VDD2
12
Character Line
CHARA
8
control control
counter counter
Horizontal
character
size
Horizontal
OSCIN 6 register
character
size
OSCOUT 7
register
Character output control
Synchronization
Timing generator
signal generator
SYNIN 17
Horizontal
Horizontal
character character
SEPC 18
size
size
register
SEPOUT 19 register
SEPIN 20
CTRL3 22
21 4 2 3
CTRL2 CTRL1 XtalIN XtalOUT BLANK CVIN
J
CDR-HD1500
RAM
Display
write
control
address
register
counter
Display
RAM
Decoder
Font
RAM
Shift
Background control
register
Video output control
5 15 13
CVOUT
49