Fluke ScopeMeter 123 Service Manual page 157

1 2
A
C212
C211
4p7 4p7
R205
511E
C213 C214
4p7 4p7
R208
B
511E
C
C204
120p
INPUT
CHANNEL B
HF
BLOCK
D
X100
7 PROBE_B
[4,H7]
C248
10n
LF
R201 R202
5
E 487K 487K
6
INPUT B
ptc C202
(grey input)
100n
R206
C206
500E
4n7
COMMON
F
(black input)
3 4
R210 R211 R212 R213
2K15 10M 10M 10M
C205
10u R220
10M
C216
4p7
R217
215E
C218 C219
4p7 4p7
R225
68E1
C217
10p
C222 C223
4p7 4p7
R219
R216 464E
215E
C221 C224
33p 33p
R218 R221
68E1 68E1
C207
470p
AC/DC
R209
2K15
C201
R203
22n
1M
2 3
4
R204
K271 26K1
R237 R238 R239 R240
56K2 56K2 56K2 56K2
R241 R243
215K 909K
50PPM 50PPM
C245
R242
C242 1n
147K
1n C246
1n
50PPM
REFATT
REF_BUS
[3,H8]
123
Service Manual
5 6
N201
10 8
DCBIAS VATTP3V3
R214 11
GNDATT
10M
9
VATTN3V3
13
HF0
33
VAMPPSUP
14 GNDREF 34
SWHF0
12
GNDHF0
16 VAMPN3V3 32
HF1
7
VP5V
17
SWHF1
15 3
GNDHF1 GNDDIG
19 30
HF2 VDIGN3V3
VDIGN3V3 6
4
CERR1
18
SWHF2
20 CERR2 5
GNDHF2
POS 1
21
HF3
22
C231 GNDHF3
ADDRESS 23
0p68
35
FB0
R231
1M OFFSET 44
C232
50PPM
4p7
37
FB1
C-ASIC
R232
100K
OQ0258
C233
50PPM
47p
38 24
FB2 DACTEST
R233
10K
C234
50PPM
470p
40
FB3
R234
27
1K
C236
ADC
50PPM
4n7
41
FB4
R236 28
MIDADC
100E
50PPM
39
FBC
1206
29
TRIGGER
42
LF
2
GPROT
36
CALSIG
43 31
PROTGND TRACEROT
SCLK SDAT
R246
215K
9-8
7 8
R282
10E
C282
100n
R284
10E
C284
R286
100n
10E
C286
100n
R289
10E
R288
10E
C289
C288 100n
100n 22u
C290 C291
C258 100n 100n
150p TP251
C252
15n
TP252
C253 R255
22n 178K
TP253
R261 R256
100K 100K
C256
R260
1n
51K1
TP254
R257
100K
TP255
TP256
R258
287E
TP258
R259
100E
C259
100p
Figure 9-2. Circuit Diagram 2, Channel B Circuit
9
L281
47u +3V3A
[5,C16]
C281
22u
L282
47u -3V3A
[5,C16]
L283
47u +5VA
[5,B16]
C283
22u
APWM_BUS
[4,D1]
POS_B
OFFSET_B
REF_BUS
[3,H8]
REFN
DACTESTB
[5,J2]
ADC_B
[4,I1]
C261
100n
MIDADC_B
[4,J1]
TRIG_B
[3,C1]
C262
4p7
TRACEROT
[3,F13]
SDAT
[4,I7]
SCLK
[4,I7]
ST8087
970604
ST8087.WMF