Tektronix 7B70 User manual

TA BLEO F CO
N T EN TS
SE CTION 1
S E CTIO
N 2
S PE CI F ICATIO
N SP
age
Intro d uction
1-1
E lectrical C h
aracteristics
1-1
Swee p
R ate
1-1
Swee p
Accuracy
1-1
Swee p
L ength
1-1
Swee p
H
ol
d -Off Time
1-1
E xternal
H orizontal Am p lifier
1-1
Deflection F actor 1-1
F re q uency R es p onse
1-2
Trigger Sensitivity
1-2
Internal
Trigger J itter
1-2
E xternal Trigger
In p ut
1-2
Ρ - Ρ
Auto Sensitivity 1-2
E nvironmental
C h aracteristics
Altitu d
e
1-2
Ph
ysical C h aracteristics
F inis h
1-2
Dimensions
1-2
W eig h t
1-2
O PER ATI NG I N ST RU
CTIO NS
General
2-1
Installation
2-1
F ront Pan el Controls
2-1
Test Setu p Ch art
2-4
General O p erating
Information
2-4
Swee p Calibration
C h ec k
2-4
Sim p lifie d Op
erating Instructions
2-4
N ormal Swee p2-6
M agnifie d Swee
p2-6
Delaye d Swee
p2-6
P us h button
Switch L ogic
2-6
Triggere d L ig h t
2-6
Trigger M ode
2-7
Trigger Cou p
ling
2-8
Trigger Source
2-9
Trigger Slo p e2-10
Trigger L evel
2-10
H
orizontal Sweep R ate
2-10
Sweep M agnifier
2-12
H orizontal P osition
Control
2-12
Display M od e2-12

TA
BLE O F CO
N T EN TS (cont)
S E CTIO N 2 O PER ATI NG I N ST RU CTIO N S
(cont) Page
A pp lications
2-13
General 2-13
F
re q uency Com p arison 2-13
Time Duration
M
easurements 2-14
Determining
F
re q uency 2-15
Risetime
M
easurements 2-15
Delaye d Sweep Time M easurements
2-16
Delaye d Swee p M ag n ification 2-17
Dis p laying Com p lex Signals U sing Delayed Swee p2-18
Pulse J itter M easurements 2-18
Χ - Υ Ph ase M easurements 2-19
S E CTIO N 3 CI RC U IT D E SC R I P TIO N
Intro d uction 3-1
B loc k Diagram Descri p tion
3-1
Detaile d Circuit Descri p tion 3-1
Trigger In p ut 3-1
Trigger Am p lifier 3-2
In p ut Stage 3-3
Peak Detector 3-3
Slo pe Com p arator 3-4
Out p ut Stage 3-4
Trigger Generator 3-4
Trigger Pulse Generator 3-4
Sweep Gate Stage 3-4
Triggere dH ol d -Off Stage 3-5
B rig h t L ine Auto 3-5
External H orizontal Am p lifier 3-5
Time- B ase Generator 3-6
General 3-6
N
ormal
Trigger M
ode O p eration 3-7
Single
Swee p
Op eration
3-8
Alternate O p eration 3-8
Delaye d Swee p Op eration 3-9
H orizontal Pream p3-9
Rea dou t B loc k3-9
SE CTIO N 4 M AI N T ENAN C E
P
reventive M aintenance 4-1
General 4-1
Cleaning
4-1
V isual Ins p ection
4-1
Transistor C h
ec
k s
4-1
Recalibration 4-1

TABLE OF
CONTENTS (cont)
CHANGE INFORMATION
Abbreviations and
symbols used in this manual are based on or
taken directly from IEEE
Standard 260 "Standard Symbols
for
Units", MIL STD-12B
and other standards of the electronics
industry . Change
information, if any, is located at the rear of
this
manual .
SECTION 4 MAINTENANCE
(cont) Page
Troubleshooting 4-2
Troubleshooting Aids
4-2
Troubleshooting Equipment
4-3
Troubleshooting Techniques
4-3
Corrective Maintenance
4-5
Obtaining Replacement Parts
4-5
Soldering Techniques
4-6
Component Replacement
4-7
Instrument Repackaging
4-8
SECTION 5 PERFORMANCE CHECK/CALIBRATION
Introduction
5-1
Test Equipment Required
5-1
Short Form Procedure
5-2
Performance Check/Calibration Procedure 5-4
General
5-4
Preliminary Control Settings
5-4
Check/Adjust Steps (refer to Short-Form
Procedure
for index to steps)
5-5
SECTION 6 ELECTRICAL PARTS LIST
Abbreviations and
Symbols
Parts Ordering Information
Index of
Electrical Parts List
SECTION 7 DIAGRAMS
AND MECHANICAL PARTS ILLUSTRATIONS
Diagrams
Mechanical Parts Illustrations
SECTION 8 MECHANICAL
PARTS LIST
Mechanical
Parts List Information
Index of
Mechanical Parts Illustrations
Mechanical Parts List
Accessories

Intro d uction
© A
S
E CTIO N 1
7 Β 70
S PE CI F I CA ΤΙΟ
Ν
C h ange info r mation, if any, affecting t h is sectio n will b e found at t he r ear of t h e m αηυαΙ .
The 71370 Time Base
U nit is designed specifically fo r use
with Te k t r onix 7700-se
r
ies oscillosco
p
es .
However, it is
com p ati b le wit h all 7000-series oscillosco p es . T he 71370
p rovi d es cali b rate d swee p s from 5 secon d s/ d ivision to 0 .02
microsecond / d ivision . T he Χ 10 M AG N I F I ER exten d s t h e
cali b rate d sweep to 2 nanosecon d s/divisio n . Swee p rates
may b e varie d continuously (u n cali b rate d ) between cali b ra-
te d ste p s . Swee p trigge r ing is to 200 mega h e r tz or ve r tical
.am p lifier b andwi d t h , w h ic h ever is less . T h e 71370 featu r es
an
external h orizontal am p lifie r to display sig n als applie d to
TA BLE 1-1
ELE CT R ICA LC HA R ACT ER ISTICS
ί
7 Β
70
t h e ΕΧΤ V O L TS IN co nn ector . T h e swee p free- runs to p ro-
vi d eα b rig h t b ase line in t he a b senceof ade q uate triggeri n g
sig n al in Ρ - Ρ A U TO an d AU TO trigge r i ng mo d es .
T h ePerformance C h ec k P r ι ce du re give n in Section 5
provi d es α convenient met hod of c h ec k ing performance of
t h is i n str u ment . T he following electrical ch aracteristics
apply at an am b ient tem p eratu r e of 0 ° C to +50 °
C,
un
less
ot
h erwise note d . W armu ptime
for
give
n accu r acy is 20
mi n utes .
C h aracte r istic Performan ce
E xclu de Following Start of Swee
p ; 50 ns
P ortio n s of Magni-
fie d Swee p End of Swee p ;
beyon d 100 d ivisions
Swee p L en gt h 10 .0 d ivisio n s
to 13 d ivisio n s .
Sweep H ol d -Off Time
5 s/ d iv to 5 μ s/ d iv 1 .5 times t he TIME/DIVISION set-
ting or less .
2 μ s/ d iv to 3 .5 microseconds or less .
0 .02 μ s/div
External H o r izontal
Amplifier
Deflection Factor
ΕΧΤ
VA R IA BLE 25 millivolts/ d ivisio n with in 5 milli-
F ully Cloc k -
volts/ d ivisio n .
wise
ΕΧΤ = 10
VA R IA BLE 250 millivolts/
d ivision with i n 50
Fu lly Cloc k - millivolts/divisio
n .
wise
VA R IA BLE
At least 10 :1
R ange
C h
aracteristic Perfo r ma n ce
Swee pR ate
Calibrate dR ange 5 secon
d s/division to 0 .02 micro-
secon
d/d ivision in α 1-2-5 se quen ce .
Χ 10 mag
n ifier extends swee p rate
to 2 nanosecond
s/divisio n .
VA R IA BLE R ange Co n tin u ously va
r
ia
b
le
b etween cali-
(uncalibrated) b rated sweep r ates . Exten
d
s un
cali-
br ate d swee p r ate to at least
12
.5
secon d s/ d ivision .
Sweep
Accu r acy M easure d in 7700-series
mainframe .
Time Interval
+15
°
C
to
+35
°
C 0 ° C to +50 ° C
Ove
r Center 8 U nmag
M ag U nmag M ag
d
iv
5
s/
d iv to 0 .1
s/div and0 .2 3%
3 .5% 4% 5%
μ s/div to 0 .02
μ s/div
50
ms/div to
2% 2 .5% 3% 4%
0 .5 μ s/ d iv
Over any 2 div
interval with i n 5% 7%
ce n ter 8 div

Specification-71370
T h is
instrument will meet t he electr ical c h a
r
acter
istics
given
in Table 1-1 over t he following environme
n tal
limits .
Altitude
Non-operating
F inis h
Dimensions
W eig h t
TA BLE 1-2
ENV
I R O NMEN TA LC HAR ACT ER ISTICS
C h aracteristic
C h aracte r istic
TA BLE 1-1 (cont)
P
e r fo r mance
To 50,000 feet and -55 ° C .
TA BLE 1-3
PH YSICA LC HA R ACT
ER ISTICS
P erformance
F ront panel is ano
d ize d aluminum .
14 .583 inc h es lo n g by 2 .75 inc
h
es
wi d e b y 5 inc h es h ig h .
Ap p roximately 2 .88 p ounds .
C h aracte r istic
Pe r formance
E xte r nal T r igger Input
M aximum In p ut 500 volts
(DC
+P
ea k AC) . 500
V
oltage volts (P-
Ρ
AC)
at 1 k ilo h ertz or less .
Input R and C 1 mego
h m with in 2°/ ο , 20 picofarads
with
in 2p icofa r ads .
L evel R an ge
( E xcl ud ing
Ρ - Ρ
A U TO)
ΕΧΤ At
least +1 .5 volts to -1 .5 volts .
ΕΧΤ
_
10
At least +15 volts to -15
volts .
Ρ - Ρ A U TO
Operation
Sensitivity
0 .5 div Internal, 125
millivolts Ex-
ternal, 200 Hz to 20 MHz .
Upp er
fre qu ency andamplitude
limits
same as N O RM A L T r igger
Sensiti-
vity .
L ow F re q uency
Mu
st
T r igge r on 50 h ertz, 2d ivision
R espon se sig n al
.
TA BLE
1-1 (cont)
C ha r acteristic
Performance
Frequency
System -3 d B p oi n ts in 7700-series
R esponse
oscillosco pe .
L ower -3
d B U pper -3 d B
AC, AC LF REJ, 16
h ertz 100 k ilo h ertz
AC HF REJ
DC
-----
100 k ilo h ertz
Trigge r Sensitivity
Triggering M inimum
Trig-
F re q ue ncy gering Signal
R ange' R e q uired
Cou p
ling
ΙΝΤ ΕΧΤ
AC 30 Hz
to 20 MHz 0 .3 div 75
mV
20 MHz to
1 .5 d iv 375 mV
200 MH z
AC
LF REJ 2 30 kH z to
0 .3 div 75 m V
20 MHz
20 MHz to
1 .5 div
275 m V
200 M H z
ACHF
REJ 30 H z to 50
kH z 0 .3 d iv 75 m V
DC DC
to 20 MH z 0 .3 d iv 75
m V
20 MH zto
1 .5 div 375 mV
200 MHz
'On
I n ter n al Triggering Only ; the
specified u p p er -3 d B fre q uency
of t h e V ertical System re p laces
upp er limit frequencies in t
h
e
a b ove table w
hen t he nu mber in
t he ta b le is greater t h an t he -3 d B
fre quen cy of the V ertical System .
Ζ W ill not trigger on sine waves of 3
divisions or less internal or 1 .5
volts external below 120 Hz .
Single Swee p Triggering re q
uirements same αε
normal sweep .
Wh en triggere d ,
swee p generator
p r oduces οηε
sweep only .
Internal Trigge r J itte
r 1 nanosecon d or less at 150 mega
h ertz .

General
S
E CTIO N 2
OPERATING
INSTRUCTIONS
Ch ange information, if an y , affecting t h is
section will
be found
at
t he rear of t
h e manual .
T he 71370 p
lug-in unit op erates with α Te
ktronix
7000-series in d
icator oscilloscope andα 7A-series
vertical
p lug-in unit to
form α com p lete oscillosco p e
system .
To
effectively
use t he 71370 its op eratio n
and ca p abilities
s h ould be k nown . T h is section d escribes
t he op eration of
t he front- p anel controls, gives first-time
an d general op era-
ting informatio n an d lists some
basic app licatio n s for t h is
instrument .
Installation
T he
71370
is designe dto o p erate in t he horizo n
tal p lug-in
com p artments
of Te k troni x7000-series oscillosco p es
. T h
e
71370
can also be i n stalle d in α vertical p lug-in
com p artment
to p rovi de α swee p t h at runs vertically on
t he CR T . How-
ever,
w h en used in t h is manner, t h ere is no
retrace blank ing
or
internal triggering p rovision and t he unit m ay
not m eet
t
h
es
p ecifications given in Section 1 . T h e instructions
in
t h is manual are written for use of t he 71370 in αh
orizontal
p
lug-in com p
artme n t of t h e oscillosco pe .
Wh en t h
e
71370
is used wit h an oscillosco p e w h ic
h h as
two h
orizontal p lug-in co mp artments, install t h is unit
in t he
Β (rig h t) com p artment . T hen, if αd elaying-swee punit
is
installe
d
-in t he Α (D EL AYI NG TIME B AS E ) com p
art
m
ent,
d elayed -swee pop
eration is available . T h e 71370 will op
erate
F ig . 2-1 . L ocatio n of
r
elease
latc h .
O p erating Instructions-71370
p rop erly in t he Α com p artment for all h orizontal mo d es of
o p eration exce p t delaying swee p .
To
install t he
71370
into α p lug-in com p artment, push it
in until it fits firmly into t he in d icator p lug-in com p art-
ment . To remove, pull t he release latc h (see F ig . 2-1) to
disengage t h e unit from t h e in d icato r an d pull it out of t h e
plug-in com p art m ent . E ve n t
h
oug
h
t h e
horizon
tal gain of
t
h
e in
d
icator oscillosco pe is
stan d
ar
d
ize
d
to minimize a
d -
j ustment
w
hen inserting p lug-in units, t h
e
s w
eep
calibration
of t h e 71370 s h ould be c h eck ed w hen it is inserted into t h e
indicator to verify measure m ent accuracy . T he procedure
for c hecking t h e unit is give n under Swee pCalibration
C heck in t h is section .
General
Triggering
Controls
L E VEL /S L O PE
T R IG'D
F R ON T- P AN EL CON TR O L S
All controls re q uire dfor t he o p eration of t h e 71370 are
locate
d on t h e
fro nt p anel of th e un it (see F ig . 2-2) .
To
ma ke full use of t h e cap abilities of t h is instrument,
t h
e
op erator s h ould be familiar with t he f unction an
d
use of
each of t hese controls . Α brief d escri p tion of t he front-
pan el controls an d connector is gi v en h ere . M ore detaile d
information is given un d er General O p erating Information .
Selects t h e am p litude point an d
slo pe of
trigger signal on w h ic h t he
swee
p is
triggere
d . Wh en t he in d ica-
tor line
on
t he outer ring
is to
t he
left of center, t h
e swee p
is triggere d
on t h e p ositive-going slo p e of t he
trigger signal, as s h own by t he
positive-going waveform . To t he
rig h t of center, t h e sweep is trig-
gere d on t he negative-going slo pe of
t he trigger signal as s h
own by t he
negative-going waveform .
L ig h t in d icates t h at t he
swee p
is
triggere d an d will p ro d uce α
d
is p lay
wit h correct setting of t he POSI-
TION
control an
d
t hecontrols on
t he associate d vertical unit and indi-
cator oscillosco pe .