Voltage Diagram; Front Unit - Icom IC-756PRO Service Manual

SECTION 10

VOLTAGE DIAGRAM

CP101

10-1 FRONT UNIT

J101
5VF
MUP
MAIN DIAL UP MAIN DIAL DOWN
MDN
M UP 4.6V GND
M DN 4.6V
CP104
S1
EVQ-VCJF0324B FRONT
J1 W4 J120
RUP RUP
UP
5VF 5VF
E
RDN RDN
DN
GND
GND
GND
GND
RIT DIAL UP RIT DIAL DOWN
GND
RSA 4.8V GND
RIT BOARD GND
RSB 4.8V
FRONT
J201
J1 W6
F5K
R201
F4K R202
MODE BOARD F3K
R203
F2K R204
F1K R205
S1 S2 S3 S4 S5 SPEK
R206
EXTK R207
FILK
R208
(F-1) (F-2) (F-3) (F-4) (F-5)
AMK R209
CWK
R210
SSBK R211
KI2
KI1
S6 S7 S8 S9 S10 S11 5VF
GND
GND
(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 S18
(A) (B) (C) (D) (E) (F) (G)
C2 0.1
FRONT
J1 J221
W7
SPLK
1K
3K
7K
10K
S1 S6 S10 S14 S18 S24 14K
SPLK 1K 3K 7K MUPK PBTK 18K
21K
(SPLIT) (1.8) (3.5) (7) (UP) (PBT-CL)
24K
S2 S7 S11 S15 S19 S25 28K
10K 14K 18K MDNK NOTK 50K
GENK
(DW) (10) (14) (18) (DOWN) (NOTCH)
FINK
S3 S8 S12 S16 S20 S26 MPWK
21K 24K 28K MWK MPRK
GND
(CHANGE) (21) (24) (28) (MW) (RIT)
S4 S9 S13 S17 S21 S27
GENK 50K FINK MCLK
FRONT
J2 J241
(V/M) (GENE) (50) (F-INP) (M-CL) (∆TX) W8
MUPK
S5 S22 S28 MDNK
TSK MWK
MCLK
(M/S) (TS) (CLEAR)
TSK
S29 S30 S23 XFCK
MPWK MPRK XFCK LOCK
PBTK
(MP-W) (MP-R) (XFC)
NOTK
S31 KI4
LOCK 5VF
KI3
(LOCK)
LDV
LOCD
TXD
RXD
NOTD
PBTD
GND
Q1 DS1 Q4 DS4 GND
DTC114EE R8 CL-200HR DTC114EE R11 CL-220YG
GND
5.6k 1k
GND
GND
(LOCK) LED (NOTCH) LED GND
Q2 DS2 Q5 DS5
DTC114EE R9 CL-200HR DTC114EE R12 CL-220YG
ON 4.5V
5.6k 1k
OFF 0V
(TX) LED (TWIN PEAK FILTER) LED
J801
Q3 DS3
to
DTC114EE R10 CL-220YG CFL+
ON 4.5V LCD
680
OFF 0V
J802
(RX) LED
to
CFL-
LCD
TEN-KEY BOARD
10 - 1
CP102 CP103
IC101a IC101c
uPD4030BG uPD4030BG
14 8
1 10
R124 1M
3 9
2
R122 R123 14
R102 1
220k 100k
8 10 7 15k MSA
2 C406
9 IC102a
3 10
R104 7 MC14071BFEL
IC102c 47k
5
MC14071BFEL 5 4
4 6 C405
6 0.1 4.8V
R128 1M
IC101b
R126 R127
IC102b uPD4030BG 0.1uS
220k 100k
12 11 MC14071BFEL
13
12
IC102d 11 1.5V
13
MC14071BFEL
R103 IC101d
15k
uPD4030BG
1
PC3/AN11
5VF 2
AVSS
3
TEST
C401 X401 4
12p CR-567 X2
5
X1
F5K 6
1k VSS
C402
1k F4K 7
12p OSC1
F3K 8
1k OSC2
1k F2K 9
RES
1k F1K 10
MDO
SPEK ASL0 11
1k
P20/IRQ4/ADTRG
1k EXTK MSB 12
P21/UD
FILK ASL1 13
1k IC411 IC401
BU4051BCFV P22 HD6473834H
1k AMK ASL2 14
P23
CWK 1 16 F1K 15
1k X4 VDD P24
1k SSBK 2 15 F2K 16
X6 X2 R402 P25
KI2 3 14 F3K 17
X X1 1k P26
KI1 4 13 F4K 18
X7 X0 P27
5VF 5 12 F5K 19
X5 X3 P30/SCK1
6 11 SSBK 20
INH A P31/SI1
7 10 CWK 21
VEE B P32/SO1
8 9 AMK 22
OFF 4.8V VSS C P33/SCK2
A 0V KI4 FILK 23
P34/SI2
B 1.2V EXTK 24
OFF 4.8V P35/SO2
C 2.4V
E 0V KI3 SRES SPEK 25
D 3.7V P36/STRB
F 1.2V
G 2.4V
MUDK
DASH
DOT
D421 D423
DAN222 DAN222
SPLK
5VF
R404 47k
R405 47k
D422
R221 1k SPLK
DAN222 R406 47k
R222 1k 1K DOTK R407 47k
R223 1k 3K DSHK
R224 1k 7K
D425 D424
R225 1k 10K
DAN222 DAN222
14K
R226 1k
R227 1k 18K
21K
R228 1k
R229 1k 24K
IC881 IC501
R230 1k 28K
TA79LO8F TA79LO8F
R881
R231 1k 50K
56
R232 1k GENK MUD
I O I
FINK D431
R233 1k
DAN222 R882 G G
R234 1k MPWK
56
MPRK
R235 1k
OFF 4.8V
RIT 0V
TX 1.2V
CLEAR 2.4V D432
DAN222
R241 1k MUPK
R242 1k MDNK
R243 1k MWK
R244 1k MCLK
R245 1k TSK
18.6V
R246 1k XFCK D821 1SS322
R821
IC861 Q821 L823
R247 1k LOCK 1.2k IC821
R861 TA7805F 2SC4081 1000uH
R248 1k PBTK BA6161F
12
R249 1k NOTK 8 1
I O R824
R250 1k KI4 7 2
G 10k
5VF R862 6 3
12
R251 1k KI3 5 4
LDV
R863
R252 1k LOCD
12
R253 1k TXD
R254 1k RXD
R255 1k NOTD
R256 1k PBTD
+14V
5VF
R850 330
Q841
IC841
L801 2SB1124S
Q802 R848 470 NJM2360M
OFF 4.8V 100uH
2SB1201 LCD BACKLIGHT 1 8
DUAL WATCH 0V CS CD
MAX 4.8V R849 470 2 7
CHANGE 1.2V Q801
MIN 0V L843 ES SI
VFO/MEMO 2.4V 2SC4081 3 6
D10F-A814AY-101K CT V+
MAIN/SUB 3.7V R801 4 5
C843 GND INVIN
33k
L803 330p
L802 D801
D818HN-1107
D10F-A814AY-101K RD3.0M D841
RB050L-40
-15.4V R845
C805 Q805 L842 1.2k
15p DTC114EE SLF12565T-680M2R0
-15V
+18V
W801
Q804 Q803 +14V
2SC3647 2SC3647 5VF
5VF
+14V
R621
2.2k
S622 S621
DS621
(TRANSMIT) (POWER)
CL-200HR
R441 10k MDM2
R442 47k
Q901
(TIMER)
R443 47k DTC114EE
R444 10k
R622 R623 2.2k R624 4.7k R625 15k
R445 10k 6.8k
R446 10k KIO
S623 S624 S625 S626
(TUNER) (MONITOR) (NB) (NR) MDM1
Q902
DTC114EE
OFF 4.8V
TUNER ON 0V
MDM0
MONITOR ON 1.2V
NB ON 2.4V
CP400 NR ON 3.7V Q903
DTC114EE
75 NOTD LDV
P97/SEG40/CL1
74 PBTD
P96/SEG39/CL2 OFF 0V
73 RXD
P95/SEG38/D0 ON 4.7V
72 TXD
Q622 Q623 Q624 Q625
P94/SEG37/M
71 LOCD DTC114EE DTC114EE DTC114EE DTC114EE
P93/SEG36
70 NRO TNRD
P92/SEG35
69 NBO
P91/SEG34
68 MONO
P90/SEG33
67 TNRD MONO
P87/SEG32
66 MDM2 NBD
P86/SEG31
65 MDM1 NRD
P85/SEG30
64 MDN0
P84/SEG29
63 BKLS
P83/SEG28 R704 R706
62 HDD2
P82/SEG27 47k (RF/SQL) 47k (NR)
61 HDD1 RFL
P81/SEG26
60 HDD0
P80/SEG25
59 MAT1
P77/SEG24
58 PHNI
R701 R702
P76/SEG23 R703
57 DSHK RV-308 R705 RV-308
P75/SEG22 47k
56 DOTK AFL 47k
P74/SEG21
55 TRAK
P73/SEG20
54 NOTK
P72/SEG19 (AF) (BAL)
53 PBTK
P71/SEG18
52 LOCK NRL
P70/SEG17
51 XFCK BALL
P67/SEG16
5VF
DELL
KYSL
CMPL
R708
PWRL
2.2k
MIGL
R709
10k
R712 R714 R716 R718 R720
EVU-FLAE02B14 EVU-FLAE02B14 EVU-FLAE02B14 EVU-FLAE02B14 EVU-FLAE02B14
(MIC GAIN) (COMP) (BK-IN DELAY)
(RF POWER) (KEY SPEED)
CNTV
-7.5V
D501
1SS322
-7R5V
O
+4R5V
3.0V
3.1V 1.7V
C1401
0.1
C1402
0.1
(INPUT SELECT) (BIAS CONTROL) (BRIGHT CONTROL) (GAMMA2)
L822
CPCN
NLFC565050T-472K
IC1401
M52338FP
1.3V
1
MAIN IN R
C1404 0.1 2
CLAMP R
3
MAIN IN G
(CLAMP CONTROL) C1405 0.1 4
4.3V CLAMP G
5
MAIN IN B
6
C1406 0.1
CLAMP B
SW 7
SW
COGC GAM1 8
HD IN
CPCN 9
CP CONT
10
1.6V VCC2
11
VEE
12
FRP2 IN
COGC 13
COM GAIN
(COMMON GAIN) (GAMMA 1) COMO 14
COM OUT
BASC 15
IC1521b
R1541 BIAS CONT
M5218AFP R1544 16
10k GND
L841 5 2.2k
D10F-A814AY-101K + 7 CONT1
6
-
R1543 22k LCD CONTRAST
MAX 8.7V
MIN 0.9V
FRONT
J601 W5 J1
5VF 5VF
NOTL R601 47k NOTL NOTL
PITL R602 47k PITL PITL R3 47k
(PITCH)
PB1A PB1A PB1A
PB1B PB1B PB1B
R1
Q905 PB2A PB2A PB2A
R904 RV-314
2SB1201 PB2B PB2B PB2B
4.7k
R4 47k
GND
(NOTCH)
GND
GND
Q904 2
R905 A
2SC4081 3
6.8k B (PBT2)
1
COM
5 S1
D901 A
PB(1/2)A,PB(1/2)B 6
RD5.1M
R906 B (PBT1)
4
15k COM
A 4.8V
right
turn PBT BOARD
R915 B
10k
A
left
turn
B
FRONT L1
J941 J1
W3 HF50ACC322513-B J2
PHE PHE
DS902 DS901
R912 AFO PHO R1
CL-200YG CL-200YG
330 PHE PHE 330
R2 330
PHNI PHNI PHONE
GND
L2
GND
HF50ACC322513-B
GND
METER BACKLIGHT
GND
MAX 11.9V
MIN 5.1V GND
DS904 DS903
R914 GND
CL-200YG CL-200YG
330
PHONE BOARD
METER BACK LIGHT
FRONT
J921 J1
W1 J2
DASH DASH
DOT DOT
R917 R916 ELEC-KEY
GND
4.7k 2.2k
+ GND
- GND
GND
+ -
GND
GND
GND
GND
Q701
DTC114EE KEY BOARD
J451
SPE
CP401
to
MAIN unit
D701
SSP J352
DAN222
CP402 CHASSIS
J452 P1
SSP SSP
CP411 + SP
MEASUREMENT CONDITIONS
SSPE SSPE
VOLTMETER :50kΩ/VDC CP412 -
OSCILLOSCOPE :20MHz 1MΩ 25pF
SUPPLY VOLTAGE:13.8V
DISPLAY : 14.1MHz USB
DISPLAY BOARD
4.5V
R502
15k
-7R5V
+4R5V R501
1k
HD
POLC
+14V
R1526
C1521 0.1 100
C1409 C1201 C1211 C1221
0.1 0.1 0.1 0.1
IC1521a
C1408 8 M5218AFP
3
0.1 + 1
2 BL
-
GL
4
C1407 RL
0.1
C1522 R1527 D1201 D1211 D1221
0.1 100 MA8030 MA8030 MA8030
C1403
0.1
Q1201 Q1211 Q1221 IC542
2SA1576 2SA1576 2SA1576 TK16105M
1
32 2
VCC1
C1110
31 3
EXT IN B 0.1
30 4
SUB CONT B
29
EXT IN G
28
SUB CONT R
27 R1551
EXT IN R 100
26 GAM2
GAM2
25 GAM1
GAM1 Q1551
24 CONT1
CONTRAST 2SC4081
23 BRGT
BRIGHT
22
FRP1 IN
21
R OUT
20 IC490
SUB BIAS R Q1553 C1554
19 S-80942ANMP-DD6
G OUT 2SA1576 10
18 1
SUB BIAS B OUT
17 2
B OUT C1553 VDD
3
10 VSS
R1552
COMO
100
Q1554
2SC4081
Q1552
2SA1576
-15V
+18V
+14V
5VF
J301
LFMD R301 1k LFMD
LMFD R312 1k LMFD
SRES R313 1k SRES
R314 1k YOBI
R R315 47 R
G R316 47 G
B R317 47 B
HSYNC
R318 1k HSYNC
VSYNC R319 1k VSYNC
GND
GND
GND
from MAIN
unit J891
GND
-8V
-8V
+18V
14V
14V
14V
J321
14V
14V
14V
PHE
AFO
PHE
TMD
PWRK from MAIN
GND unit J861
GND
GND
GND
MICI
8V
MSND
MICE
SQSS
MIC BOARD
C1
0.0047
J1
7 1
OFF 4.8V 6 8 2
UP 0.6V
5 3
DOWN 1.2V
4
FRONT
J322 J2
W2
MICI MICI L1 100uH
M8V M8V
MUD MUD L3 100uH
SQLS SQLS
L4 100uH
MSND MSND
GND GND
MMICE MMICE
AFO AFO L6
HF50ACC322513-B
Q321
DTC114EE
8 Q512 J531
7 2SB1132 Q514
2SB1132
6 L5V
5 HD
VD
POLC
IC511d
Q511 NJM2902V Q515 W504 GND
D512 C513
RD5.1M DTC114EE 12 DTC114EE
0.1 + 14
13 L5V
-
RL
to
GL
Q513 LCD
BL
DTC114EE unit
5 5 R512 VCOM
CO 1 2.2k
4 GND
2 W512
4 IC511c
NC 12.1V W502
R511 NJM2902V
3 IC511b L/R
10k 4 12.1V
2 NJM2092V 10 U/D
+ 1 + 8
3 5 9
IC492 - + 7 - W506
IC511a 6
TC4S81F 11 -
NJM2092V N/P
L18V
-15V
CP5