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KX-T7436C/KX-T7436C-B
2. LCD CONTROL CIRCUIT
1) Circuit Operation
The LCD data is output from pins 32 to 35, 40 to 47 and 11 of IC6.
LCD contrast adjustment is performed by the circuit composed of Q28, Q29, R109, R108 and R106.
The contrast is determined only by the voltage level between V5 and VEE of IC203, IC204 and IC205. Higher potential
makes the contrast high.
Circuit Diagram
IC202
C203
+5V
IC201
IC203
IC205
IC204
28
4
3
2
1
3
2
1
60
59
58
57
56
55
54
53
37
36
35
34
33
32
31
30
13
59
58
57
56
55
54
53
37
36
35
34
33
32
31
30
13
2
3
4
5
6
7
8
9
10
21
23
24
11
12
13
15
16
17
18
19
27
3
4
5
6
7
8
9
10
21
23
24
11
12
13
15
16
17
18
19
27
A0
A1
A2
A3
A4
A5
A6
A7
A8
A1
A2
A3
A4
A5
A6
A7
A8
28
26
26
14
25
20
22
25
20
22
VCC
CE2
CE2
GNO
A12
CE1
OE
A12
CE1
OE
A9
A10
A11
A11
I/01
I/02
I/03
I/04
I/05
I/06
I/07
I/08
WE
I/02
I/03
I/04
I/05
I/06
I/07
I/08
WE
MA0
MA1
MA2
MA3
MA4
MA5
MA6
MA7
MA8
MA9
MA10
MA11
MD0
MD1
MD2
MD3
MD4
MD5
MD6
MD7
WE
MA1
MA2
MA3
MA4
MA5
MA6
MA7
MA8
MA9
MA10
MA11
MD0
MD1
MD2
MD3
MD4
MD5
MD6
MD7
WE
44
43
42
41
40
39
38
52
51
50
49
43
42
41
40
39
38
52
51
50
49
45
RD1
RD2
RD3
RD4
RD5
RD6
RD7
MA12
MA13
MA14
MA15
RD2
RD3
RD4
RD5
RD6
RD7
MA12
MA13
MA14
MA15
RD0
27
26
25
15
14
18
24
23
22
21
17
16
DB0
DB1
DB2
DB3
CS
RES
RS
DB4
DB5
DB6
DB7
R/W
E
9
12
19
18
CPO
SYC
MA
D2
29
20
VDO
GND
47
46
5
10
10
11
D1
CL2
MB
FLM
CL1
8
6
7
CR
C
R
+5V
R201
CN201
CN2
C88
R109
R108
R107
R103
R106
R105
R102
Q29
Q28
Q27
Q30
R104
+5V(V1)
+5V(V1)
+5V
+5V
+5V
+5V
C206
92
V1
V3
V4
VD0
VD0
D13
D12
D11
P/S
VSS
VEE
SDI
LOAD
N
CP
CDI
CDO
V1
V3
V4
VD0
VD0
DISP-OFF
D13
D12
D11
P/S
VSS
CDI
89
88
91
90
96
95
94
85
86
+5V
+5V
C204
C205
90
91
82
92
89
88
84
96
95
94
85
86
99
VEE
SDI
LOAD
M
100
87
97
98
93
01
02
03
04
05
07
08
09
010
011
013
014
015
016
017
019
020
021
022
023
025
026
027
028
029
031
032
033
034
035
037
038
039
040
041
043
044
045
046
047
049
050
051
052
053
055
056
057
058
059
061
062
063
01
02
03
05
06
07
08
09
011
013
014
015
017
018
019
020
021
023
024
025
026
027
029
030
031
032
033
035
036
037
038
039
041
042
043
044
045
047
048
049
050
051
053
054
055
056
057
058
059
060
061
062
063
1
2
3
5
6
7
8
9
11
13
14
15
17
18
19
20
21
23
24
25
26
27
29
30
31
32
33
35
36
37
38
39
41
42
43
44
45
47
48
49
50
51
53
54
55
56
57
58
59
60
61
62
63
064
065
067
068
069
070
071
073
074
075
076
077
079
080
1
2
3
4
5
7
8
9
10
11
13
14
15
16
17
19
20
21
22
23
25
26
27
28
29
31
32
33
34
35
37
38
39
40
41
43
44
45
46
47
49
50
51
52
53
55
56
57
58
59
61
62
63
64
65
67
68
69
70
71
73
74
75
76
77
79
80
31
32
27
36
40
38
28
29
VEE
01
02
03
04
05
06
07
08
09
010
011
012
013
014
015
016
017
018
019
020
021
022
023
024
025
026
027
028
029
030
031
032
033
034
035
036
037
038
039
040
041
042
043
044
045
046
047
048
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
1
2
3
4
5
6
7
8
M
DI01
CP
V5
V2
30
34
33
34
33
DISP-OFF
VDO
V1
VSS
RS/LS
CP
87
97
98
93
100
99
FR1
SW50
IC206
2
3
6
7
V1
V2
V3
V4
VCC
VIN2
VIN3
8
5
4
1
GND
R203
R101
R114
8
7
4
3
27
26
25
24
23
32
31
30
29
28
22
11
6
17
2
9
10
13
12
16
18
19
20
21
15
14
8
7
4
3
27
26
25
24
23
32
31
30
29
28
22
11
6
17
1
1
2
9
10
13
12
16
18
19
20
21
15
14
33
34
35
36
5
+
–
32
56 57
33
34
35
40
41
42
43
44
45
46
47
11
RA0 RA1
R30
R33
R32
R31
R60
R61
R62
R63
R70
R71
R72
R73
D2
IC6
R[60]
R[61]
R[62]
R[63]
R[32]
R[33]
R[31]
R[70]
R[71]
R[72]
R[73]
C200
C201
C201
R202
R[30]
D[2]
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