2445 Service
A1— M AIN BOARD
(CONT)
ACRONYM DICTIONARY
CIRCUIT
SCHEM
CIRCUIT
SCHEM
CIRCUIT
SCHEM
NUM BER
N UM BER
NUM BER
NUM BER
NUM BER
N UM BER
R556
5
R907
5
U700
5
R557
5
R910
5
U700
11
R558
5
R912
5
U735
6
R560
5
R924
5
U735
6
R600
6
R936
5
U735
6
R601
6
R937
5
U735
6
R602
6
R940
5
U735
6
R605
6
R941
5
U800
6
R606
6
R943
5
U800
11
R607
6
R944
5
U850
5
R608
6
R945
5
U850
5
R614
6
R950
5
U850
6
R615
6
R951
11
U850
11
R617
6
R952
5
U860
5
R618
6
R956
6
U860
5
R619
6
R957
6
U860
6
R622
6
R972
6
U860
11
R624
6
R973
6
U900
5
R638
6
R981
5
U900
11
R639
6
R995
6
U910
5
R642
6
S615
6
U910
5
R643
5
U100
4
U910
11
R644
5
U100
11
U950
6
R645
5
U110
4
U950
11
R646
5
U110
11
U975
5
R650
6
U120
4
U975
5
R651
5
U120
11
U975
6
R652
5
U130
4
U975
6
R653
5
U13Q
4
U975
11
R654
5
U130
4
U980
5
R655
5
U130
4
U980
5
R659
6
U130
4
U980
6
R669
5
U130
4
U980
6
R670
5
U130
4
U980
11
R671
5
U130
11
VR125
11
R672
5
U140
4
VR225
11
R678
5
U140
11
VR550
5
R700
11
U150
4
W101
11
R701
11
U150
11
W102
11
R702
11
U160
4
W103
11
R707
5
U160
4
W104
11
R708
5
U160
4
W105
11
R709
5
U160
4
W106
6
R710
5
U160
11
W107
5
R713
5
U165
4
W108
5
R723
5
U165
5
W109
11
R724
5
U165
5
W121
11
R731
6
U165
5
W121
11
R732
6
U165
11
W122
5
R733
6
U170
4
W122
11
R734
6
U170
11
W141
6
R735
6
U200
4
W141
6
R736
5
U200
11
W171
4
R737
5
U300
4
W172
4
R738
5
U300
11
W194
4
R741
5
U350
5
W666
5
R742
5
U350
5
W677
5
R743
5
U350
11
W916
6
R744
5
U400
6
W917
6
R745
5
U400
11
W918
6
R746
5
U450
4
W919
6
R750
5
U450
4
R800
6
U450
11
R801
6
U475
6
R802
6
U475
6
R803
6
U475
6
R804
6
U475
6
R805
6
U475
6
R806
6
U485
6
R809
6
U485
6
R811
11
U485
6
R817
6
U485
6
R820
6
U485
6
R821
6
U500
5
R822
6
U500
11
R823
6
U550
5
R850
6
U550
5
R852
5
U550
5
R853
5
U550
5
R855
6
U550
5
R856
6
U600
6
R858
6
U600
11
R860
6
U650
5
R904
5
U650
11
The following listing explains some of the less obvious
acronyms and signal labels used on this schematic.
Acronyms and labels not shown in this listing may be
included in the circuit descriptions (Section 3) and should
be obvious if a little thought is given to the intended circuit
function.
AP O +. . . auxiliary pickoff, noninverting
ATTN CLK . . . attenuator clock
ATTN STRB . . . attenuator strobe
BDCA . . . bypass delay comparator A
BDCB . . . bypass delay comparator B
BPO+ . . . second auxiliary pickoff, noninverting
BWL . . . bandwidth lim it
BYP . . . bypass
CC . . . control clock
CD . . . control data
CHI OVI___ CHI overload
CH2 OVI___ CH2 overload
CHI PA CLK . . . CHI preamp clock
CH2 PA CLK . . . CH2 preamp clock
CHI PRB - CH4 PRB . . . CHI - CH4 probe encoding
CONT DATA . . . control data
CTC . . . capacitor, tim ing compensation
DAC MUX1 INH . . . DAC multiplexer 1 inhibit
DAC MUX1 AO . . . DAC multiplexer 1, address b it 0
DAC MUX1 A1 . . . DAC multiplexer 1, address b it 1
DAC MUX1 A2 . . . DAC multiplexer 1, address b it 2
DAC MUX1 IN . . . DAC multiplexer 1 input
DO+ . . . display output, noninverting
DO— . . . display output, inverting
DON3 . . . display output, negative CH 3
DOP3 . . . display output, positive CH 3
DON4 . . . display output, negative CH 4
DOP4 . . . display output, positive CH 4
GA3 . . . gain 3
GA4 . . . gain 4
SI . . . scope identification bit
SIL . . . slow intensity lim it
TPO— . . . trigger pickoff, inverting
TP03 . . . CH3 trigger pickoff
TP04 . . . CH4 trigger pickoff
TPT— . . . trigger p icko ff reverse termination
T X Y . . . triggered X-Y
Summary of Contents for 2445
Page 1: ...Tektronix 2445 OSCILLOSCOPE SERVICE INSTRUCTION MANUAL ...
Page 11: ...2445 Service 3829 01 The 2445 Oscilloscope ...
Page 44: ...Theory of Operation 2445 Service 3831 10A Figure 3 1 Block diagram ...
Page 45: ...Theory of Operation 2445 Service 3831 10B Figure 3 1 Block diagram cont 3 3 ...
Page 210: ...3829 58 Figure 9 4 2445 block diagram ...
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Page 217: ......
Page 219: ...2445 382 72 ...
Page 222: ...2445 ...
Page 231: ...A 1 t C t t F t G t H t ...
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Page 238: ...2445 392 1 75 ...
Page 244: ......
Page 247: ...A 1 C _____ D E F G H J 2445 3811 74 ...
Page 248: ...1 2 3 4 5 6 7 8 9 i o 2445 DISPLAY SEQUENCER TRIG GERING A4B SWEEPS ...
Page 253: ......
Page 263: ... 0 2445 J8 i S ...
Page 264: ...1 2 3 4 5 6 7 i 8 I i 9 10 2445 READOUT ...
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Page 283: ... 8VJNR EG 3S 5 fROM P232 5 10 A 15VUNREG 8S F R O Mn i 2445 3 0 2 S 8 I ...
Page 286: ...2445 3823 82 ...
Page 290: ...B H le w o q 87V T S o I R v n i U1 R1873 PARTIAL A9 HIGH VOLTAGE BOARD 2445 ...
Page 299: ...2445 Service DAC REF A5 CONTROL ADJUSTMENT LOCATIONS 3 ...
Page 300: ......
Page 304: ...2 R E TU R N T O 1 ...
Page 305: ...ERROR MESSAGE DIAGNOSTICS ...
Page 306: ...ERROR MESSAGE DIAGNOSTICS ...
Page 307: ...O A A C t rnra g i tiw c t 3829 89 ...
Page 308: ...RETURN TO ...
Page 309: ...FRONT PANEL TROUBLESHOOTING ...
Page 310: ...FRONT PANEL TROUBLESHOOTING ...
Page 311: ...2445 Service 3829 90 ...
Page 316: ...R E TU R N T O v 1 y ...
Page 317: ...SWEEP TROUBLESHOOTING PROCEDURE ...
Page 323: ......
Page 324: ...2445 Service 3829 85 ...
Page 325: ......
Page 326: ... KERNEL NOP DIAGNOSTIC PROCEDURE ...
Page 327: ...10 POWER SUPPLY TROUBLESHOOTING PROCEDURE 3829 94 ...
Page 330: ......
Page 334: ...2445 Service REGULATOR TROUBLESHOOTING PROCEDURE 3829 93 ...
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Page 346: ...12 2445 SERVICE ...
Page 347: ...2445 SERVICE ...
Page 348: ...2445 SERVICE ...