Icom IC-756PRO III Service Manual page 84

SECTION 10 VOLTAGE DIAGRAM
MAIN DIAL UP
M UP
M DN
S1
EVQ-VCJF0324B
UP
E
DN
RIT DIAL UP RIT DIAL DOWN
RSA 4.8V
RIT BOARD
RSB 4.8V
MODE BOARD
S1 S2 S3 S4 S5
(F-1) (F-2) (F-3) (F-4) (F-5)
S6 S7 S8 S9 S10 S11
(SSB) (CW/RTTY) (AM/FM) (FILTER) (EXIT) (SPEECH)
R1 R2 R3 R4 R5 R6 R7
6.8k 2.2k 4.7k 15k 6.8k 2.2k 4.7k
S12 S13 S14 S15 S16 S17
(A) (B) (C) (D) (E) (F)
C2 0.1
S1 S6 S10 S14 S18
SPLK 1K 3K 7K MUPK PBTK
(SPLIT) (1.8) (3.5) (7) (UP) (PBT-CL)
S2 S7 S11 S15 S19
10K 14K 18K MDNK NOTK
(DW) (10) (14) (18) (DOWN)
S3 S8 S12 S16 S20
21K 24K 28K MWK
(CHANGE) (21) (24) (28) (MW)
S4 S9 S13 S17 S21
GENK 50K FINK MCLK
(V/M) (GENE) (50) (F-INP) (M-CL)
S5 S22
TSK
(M/S) (TS)
S29 S30 S23
MPWK MPRK XFCK
(MP-W) (MP-R) (XFC)
S31
LOCK
(LOCK)
Q1 DS1 Q4
DTC114EE R8 CL-200HR DTC114EE R11
5.6k 1k
(LOCK) LED (NOTCH) LED
Q2 DS2 Q5
DTC114EE R9 CL-200HR DTC114EE R12
ON 4.5V
5.6k 1k
OFF 0V
(TX) LED (TWIN PEAK FILTER) LED
Q3 DS3
DTC114EE R10 CL-220YG
ON 4.5V
680
OFF 0V
(RX) LED
TEN-KEY BOARD
10 - 1
CP101
5VF
J101
5VF
CP102 CP103
MUP
MAIN DIAL DOWN
MDN
4.6V GND
1
R124 1M
2
R122 R123
220k 100k
4.6V 8
CP104 10
9
IC102c
5
FRONT CD4071BNSR
J1 J120
W4 6
R128 1M
RUP RUP
R126 R127
5VF 5VF
IC102b
220k 100k
RDN RDN 12
11
MC14071BFEL
GND 13
GND
IC102d
GND
MC14071BFEL
GND
GND
GND
GND
5VF
FRONT
J201
J1
W6
F5K F5K
R201 1k
F4K F4K
R202 1k
F3K F3K
R203 1k
F2K R204 1k F2K
F1K F1K
R205 1k
SPEK R206 1k SPEK
EXTK EXTK
R207 1k
FILK R208 1k FILK IC411
AMK AMK BU4051BCFV
R209 1k
CWK R210 1k CWK 1
SSBK SSBK 2
R211 1k
KI2 KI2 3
KI1 KI1 4
5VF 5VF 5
GND 6
GND 7
8
OFF 4.8V
KI4
A 0V
B 1.2V
OFF 4.8V
C 2.4V
KI3
E 0V
D 3.7V
F 1.2V
G 2.4V
S18
D421
(G) DAN222
FRONT
J1 J221
W7
SPLK R221 1k SPLK
1K 1K
R222 1k
3K R223 1k 3K
7K 7K
R224 1k
D425
10K R225 1k 10K
DAN222
S24 14K 14K
R226 1k
18K R227 1k 18K
21K 21K
R228 1k
24K R229 1k 24K
S25 28K 28K
R230 1k
50K R231 1k 50K
GENK GENK
R232 1k
(NOTCH)
D431
FINK R233 1k FINK
DAN222
S26 MPWK MPWK
R234 1k
MPRK MPRK
R235 1k
GND
(RIT)
OFF 4.8V
S27 RIT 0V
CLEAR 2.4V
FRONT
J2 J241
( TX) W8
MUPK R241 1k MUPK
S28
MDNK R242 1k MDNK
MWK R243 1k MWK
MCLK R244 1k MCLK
(CLEAR)
TSK R245 1k TSK
XFCK R246 1k XFCK
LOCK R247 1k LOCK
R861
PBTK R248 1k PBTK
12
NOTK R249 1k NOTK
KI4 R250 1k KI4
R862
5VF 5VF
12
KI3 R251 1k KI3
LDV LDV
R863
LOCD R252 1k LOCD
12
TXD R253 1k TXD
RXD R254 1k RXD
NOTD R255 1k NOTD
PBTD R256 1k PBTD
GND +14V
DS4 GND 5VF
CL-220YG
GND
GND
L801
GND Q802
OFF 4.8V 100µH
GND 2SB1201
DUAL WATCH 0V
DS5 CHANGE 1.2V
CL-220YG VFO/MEMO 2.4V
MAIN/SUB 3.7V
L803
L802
D818HN-1107
J801
D10F-A814AY-101K
to
CFL+
LCD
C805
J802 15p
to
CFL-
LCD
Q804 Q803
2SC3647 2SC3647
IC101a IC101c
BU4030BF BU4030BF
14 8
10
3 9
14
R102
1
7 15k MSA
2
C406
IC102a
3 10
R104 MC14071BFEL
7
47k
5
4
C405
4 6
0.1 4.8V
IC101b
BU4030BF
0.1µS
12
11 1.5V
13
R103 IC101d
15k
BU4030BF
1
AS0
PC3/AN11
2
AVSS
3
TEST
C401 X401
4
12p CR-567 X2
5
X1
6
VSS
C402
7
12p OSC1
8
OSC2
9
RES
10
MDO
ASL0 11
P20/IRQ4/ADTRG
MSB 12
P21/UD
ASL1 13
P22
ASL2 14
P23
16 F1K 15
X4 VDD P24
15 F2K 16
X6 X2 R402 P25
14 F3K 17
1k
X X1 P26
13 F4K 18
X7 X0 P27
12 F5K 19
X5 X3 P30/SCK1
11 SSBK 20
INH A P31/SI1
10 CWK 21
VEE B P32/SO1
9 AMK 22
VSS C P33/SCK2
FILK 23
P34/SI2
EXTK 24
P35/SO2
SRES SPEK 25
P36/STRB
MUDK
DASH
DOT
D423
DAN222
SPLK
5VF
R404
R405
D422
R406
DAN222
DOTK
R407
DSHK
D424
DAN222
IC881
TA79LO8F
R881
56
MUD -8V
I O
G
R882
56
D432
DAN222
18.6V
R821
IC861 Q821 L823
TA7805F 2SC4081 1000µH 1.2k
5VF
I O R824
G 10k
R850 330
Q841
2SB1124S R848 470
LCD BACKLIGHT R849 470
MAX 4.8V
Q801
MIN 0V
L843
2SC4081
C843
D10F-A814AY-101K
R801
330p
33k
D801
RD3.0M D841
RB050L-40
-15.4V
Q805 L842
DTC114EE
SLF12565T-680M2R0
-15V
+18V
W801
+14V
5VF
R441 10k L401
HF50ACC322513-B
R442 47k
R443 47k
R444 10k
R445 10k
R446 10k
CP400
75 NOTD
P97/SEG40/CL1
74 PBTD
P96/SEG39/CL2
73 RXD
P95/SEG38/D0
72 TXD
P94/SEG37/M
71 LOCD
P93/SEG36
70 NRD
P92/SEG35
69 NBD
P91/SEG34
68 MOND
P90/SEG33
67 TNRD
P87/SEG32
66 MDM2
P86/SEG31
65 MDM1
P85/SEG30
64 MDN0
P84/SEG29
IC401 63 BKLS
P83/SEG28
HD6433832SD66H 62 HDD2
P82/SEG27
61 HDD1
P81/SEG26
60 HDD0
P80/SEG25
59 MAT1
P77/SEG24
58 PHNI
P76/SEG23
57 DSHK
P75/SEG22
56 DOTK
P74/SEG21
55 TRAK
P73/SEG20
54 NOTK
P72/SEG19
53 PBTK
P71/SEG18
52 LOCK
P70/SEG17
51 XFCK
P67/SEG16
47k
47k
47k
47k
–8V
CNTV
+14V
IC501
TA79LO8F
D501
1SS322
-7R5V
I O
+4R5V
G
(INPUT SELECT)
D821 1SS322
IC821
BA6161F L822
CPCN
NLFC565050T-472K
8 1
7 2
1.3V
L821
6 3
HF50ACC322413-B
5 4
(CLAMP CONTROL)
COGC
1.6V
IC841
NJM2360AM
1 8
CS CD
2 7 (COMMON GAIN)
ES SI
3 6
CT V+
4 5
GND INVIN
L841 CNTV
D10F-A814AY-101K
R845
1.2k
A
B
+14V
C
D
E
KIO
F
G
H
I
J
RFL
K
AFL
L
NRL
M
BALL
N
5VF
O
DELL
P
KYSL
Q
CMPL
R
PWRL
S
MIGL
T
U
V
W
X
Explanatory notes
VOLTAGE LINE
Y
Z
AA
AB
AC
DISPLAY BOARD
-15V
AD
-18V
AE
+14V
AF
AG
AH
AI