![background image](http://html.mh-extra.com/html/nad/c-720bee/c-720bee_service-manual_703246015.webp)
R
Vdd
Din
Dout
CLK
STB
OSC
Serial I/F
Command decoder
Display memory
20bit x 16 word
Dimming circuit
20-bit output latch
Timing generator
key scan
key scan memory (4x20)
5-bit latch
4-bit latch
16-bit shift register
Data selector
G
rid driver
Segm
ent/grid driver
Segm
ent driver
LED 1
LED 5
SW1
SW4
TO
4
Key1
Key4
TO
4
20
12
8
16
8
8
8
Seg1
Seg12
Seg13/grid16
Seg20/grid9
Grid 8
Grid 1
Vdd
(+5V)
Vss
(0V)
Vee
(-30V)
uPD16311
MAIN BOARD :IC703
PIN CONFIGURATION(Top View)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
Seg1/
KS1
Seg2/
KS2
Seg3/
KS3
Seg4/
KS4
Seg5/
KS5
Seg6/
KS6
Seg7/
KS7
Seg8/
KS8
Seg9/
KS9
Seg10/
KS10
Seg11KS11
Seg12KS12
Vdd
SW1
SW2
SW3
SW4
Dout
Din
IC
CLK
STB
KEY1
KEY2
KEY3
KEY4
Grid6
Grid7
Grid8
Seg20/Grid9
Seg19/Grid10
Vee
Vdd
Seg18/Grid11
Seg17/Grid12
Seg16/Grid13
Seg15/Grid14
Seg14/Grid15
Seg13/Grid16
OSC
Vss
LED1
LED2
LED3
LED4
LED5
Vdd
G
rid1
G
rid2
G
rid3
G
rid4
G
rid5
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