Fluke 41B - Page 101

Schematic Diagrams
7
7-5
Figure 7-1. A1 Main PCA (Fluke 39 and 41B) (cont)
VCC
NC
NC
GND
CS
SK
DI
DO
U22
93C46 VCC
D
BAV99
CR1
R29
464K
VCC
D
CR6
SFH409-2
150
R36
R56
1.33K
U20
LM358DT
Q21
MMBT3906
2.7NF
C10
D
11K
R25
1K
R28
R39
4.7K
Q5
SFH309
Q1
MMBT3904
1K
R32
D
D
220NF
C11
D
U20
LM358DT
VCC
220NF
C12
D
R40
100K
R27
1K
BAV99
CR5
VCC
Q2
MMBT6429
10K
R19
R16
100K
R7
36K
VCC
D
1
C46
R35
100K
D
Q3
MMBT6429
INC
U/D
CS
VL
VW
VH
X9313
U8
10K
R24
VCC
VCC
VBT+
D
R53
20K
R49
24.9K
R52
37.4K
U21
LM358DT
D
D
VCC
R30
20K
R58
1M
R51
20K
R55
100K
Q15
MMBT6429
D
R57
220K
D
R45
1K
200
R42
VSS
R46
620K
R50
29.4K
D
VCC
U21
LM358DT
D
R54
3.3
R59
10
Q14
MMBT6429
6.98K
R47
Q16
MMBT5087
R60
100K
VCC
VCC
VCC
D
4.7K
R68
Q19
MMBT6429
10K
R66
36K
R74
VCC
LM4041EIM3-1.2
U26
VCC
100K
R72
Q17
MMBT6429
D
8
8
9
DEFAULTS MEMORY
CONTRAST CONTROL
RECEIVER
POWER RESET BACKLIGHT
LOW BATTERY DETECT
41 ONLY
TRANSMITTER
76
5
32
1
C
A
E
C
8
7
6
5
4
8
4
3
2
1
8
7
6
5
4
8
4
3
2
1
C
A
C
A
C
A
8
7
6
54
3
2
1
N
Q
N
Q
TXD
1%
1%
35V
RESET
1%
1%
1%
1%
RXD
RESET*
1%
1%
BL_K
1%
1%
1%
LOW_BAT
1%
1%
1%
TOP_WIP
WIPER
BOT_WIP
EE_UPLOW
INC_EEPOT*
CS_EEPOT*
SCK*
DOUT_EESER
DIN
CS_EESER
BL_CT
FLUKE 4X-1021
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