Tektronix 7a11 User manual

1 Ν ST F Z U
CTI
ΟΝ
ΜΑΝ
VAL .
Serial N u mber
7A11
A MPL I F I ER
Te
k tr onix, Inc
.
S . W .
M illi kan W ay
"
Ρ . Ο . Box 500
" B eaverton, Oregon 97005 " Ph one 644-0161
" Cables : Te k tro n ix
070-0984-00

1 269

WARRANTY
All Tektronix instruments are
warranted
against
defective materials and workman-
ship
for one year . Tektronix transformers,
manufactured
in our plant, are
warranted
for the life of
the instrument .
Any questions
with respect to the war-
ranty mentioned
above should be taken
up with your
Tektronix Field Engineer
.
Tektronix repair
and replacement-part
service is geared
directly to the field,
therefore all requests
for repairs and re-
placement parts
should be directed to the
Tektronix Field
Office or representative
in your area . This
procedure will assure
you
the fastest possible
service . Please
include the instrument
Type and Serial or
Model Number with all
requests for parts
or service .
Specifications and price
change privi-
leges reserved
:
Copyright ' 1969
by Tektronix, Inc .,
Beaverton, Oregon .
Printed in the United
States of America .
All rights reserved .
Contents of this
publication may not be
reproduced in any
form without permis-
sion of the copyright
owner .

TA BLE
O F CO N T
EN TS
S E CTIO
N 1
S E
CTIO N 2
S PE CI F ICATIO
N
Introduction
1-1
E lectrical
Deflection
Facto r
1-1
Gain
1-1
Fre q uency R esponse
1-1
M aximum Input
V oltage
1-2
Input R and
C
1-2
Maximum
GateCurrent
1-2
N oise
1-2
DC
Drift
1-2
Drift Wit h Ambient
Temperature 1-2
Trace ID EN TI F
Y
1-2
O FF S E T Range
1-2
O FF S E T O U
T
1-2
50
Ω Termination/Adapter
1-3
En
vironmental
Probe
1-3
Temperature
1-3
Altitude
1-3
V ibration
1-3
S h oc k
1-5
Plug-in
Altitude
1-5
Ph
ysical
Finis h
1-5
Dimension
1-5
Weig ht
1-5
O PER ATI N G I N ST
RU CTIO N S
General 2-1
Plug-in Insertion/ R emoval 2-1
P
robe
R emoval/Storage 2-1
External Controls and Connectors 2-1
Accessories Information 2-5
First Time Operation
ST EP ΑΤΤΕΝ B A L Ad ju stment 2-5
ID
EN
TI F Y 2-6
BA N D W IDT H 2-6
GAI N 2-6
PO L A R ITY 2-6
O
FF S E T 2-6
Probe Operation
2-7
Unscaled Deflection
Factors
2-7
Input Ca p acitance
2-8

TABLE OF
CONTENTS (cont)
SECTION 3 CIRCUIT DESCRIPTION
Block Diagram Description
3-1
Probe Circuit Description
3-2
Input
Amplifier
3-3
Output
Amplifier
3-4
Offset
Generator
3-5
Volts/Div Switch and Readout
3-6
Power Supplies and Output
Connectors 3-7
SECTION 4
MAINTENANCE
Preventive Maintenance
General Information
4-1
Cleaning
4-1
Visual Inspection 4-1
Lubrication
4-1
Transistor and Integrated
Circuit Checks 4-1
Recalibration 4-1
Troubleshooting
Test Equipment
4-1
General Techniques 4-2
Troubleshooting Basic
Components
4-2
Troubleshooting Chart
4-4
Corrective Maintenance
Parts Procurement
4-5
Screwdriver
Requirements
4-8
Soldering
Equipment and Techniques
4-8
Probe Data 4-9
Plug-in
Unit Data 4-10
Circuit Board Illustrations
4-12
SECTION 5 PERFORMANCE
CHECK/CALIBRATION
General
5-1
Calibration
Procedure Instructions
5-1
Performance Check Instructions
5-1
Calibration Index and Record
Instructions 5-1
Equipment Required
5-1
Detailed Procedure
5-6
SECTION 6
ELECTRICAL PARTS
LIST
Abbreviations and
Symbols
Parts Ordering
Information

TABLE OF
CONTENTS (cont)
SECTION 7

DIAGRAMS
SECTION 8

MECHANICAL PARTS LIST
CHANGE INFORMATION
Electrical
Mechanical Parts List Illustrations
Accessories
Mechanical Parts List
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 .

Fig . 1-1 .

7A11
Amplifier .

I n tro d uctio n
T h e

7A11 Am p
lifie r is α versatile p l u g-in am p lifie r u n it
w h ic h pr ovi d es α
DC to 150 MHz b andwi d t h with Te k -
tronix 7700-Se r ies
Oscillosco p es . Wh en d esi r ed, t he u pp er
f r e q uency -3 dB point can be
limited
to
20 MHz by α
fro n t- p anel switc h .
Calib r ate d d eflection factors of fro m 5 m V to 20 V per
divisio n are p rovi ded in 1-2-5 se quen ce . In ad d ition, α va r i-
able
gain control ma k es it possible to set t h e amplifier to
any deflection facto
r
between
5 mV a n d 50 V pe r d ivision .
Α p erma n en tly attac hed p robe provi d es low-input capa-
citance (2 .0 pF at 2 V / d ivision, 5 .8 pF at 5 mV /division)
w h ile mai n tai n i ng h ig h
i
np ut r esista nce (1 ΜΩ ) . BN C-
conn ecto rs can be attac he d to t he p
r
ob e
t
h ro ugh α pro b e-
tip to BN C-female a da p ter . T h is adap ter serves as t
he
p ro b e's in pu t conn ecto
r
w
hen
t he p r obe is sto
r
ed, but can
be attac
h
ed
to t he
p
r ob e ti p w h
et
h er or n ot t h e pro b e is
sto r e d in t he p l u g-in unit .
Α 50 Ω termination/adapte
r
(stan d ard accesso
r y)
pe
r -
mits impedan ce matc h i n g fo
r u
se of
t h e probe i n 50 Ω
en vi r on me n ts . Wh en t
h
e
terminatio n /ada p ter is u se d , α low
stan d i ng wave r atio (V S
WR) can b e exp ecte d . T he V S WR
can be furt h er r e
d
uced b
y i n se r ti n gα2 Χ atte nuato r i n t he
sig n al
p
ath a
h
ea
d of t he 50 Ω termi n ation/a d apter . Ap p rox-
imate values of V S
WR w h
ic
hcan beexpectedun d er both
con d itions ar e sh ow
n in Fig . 1-4 .
T he p erfo rm ance s p
ecification of the
7A
11 A mp lifie r is
d escribe d in d etail in Ta b le
1-1 . T he specification is valid
unde r t he followi ng conditio
ns
:
(M
Change info r matio n , if an y, affecting this section
will be fo und at t he r ea r of t he ma n ual
.
Calib
r atio n m ust h ave been pe r forme d at an ambient
tem p eratu
r
eb etwee
n +20 ° C and +30 ° C .
Ope r atio n m u st be wit
h
i
n
any
specifie d enviro n me n t,
in α cali br ated Oscilloscope,
after twe n ty min u tes of
wa r mup .
S E CTIO N 1
S PE CI F
ICATIO N
REV .
M AR 1974
TA BLE 1-1
7 Α 11 Amplifie r Specificatio n
7
Α 11
C h a r acte r istic Perfo r mance R e q uirement
ELE CT R ICA L
Deflectio n F actor
( VO L TS/DI V )
Calibrate d R ange 5 m V / d iv to 20 V /div ;
12 ste
p
s i n
5, 10, 20 se qu en ce
Gain
R atio W it h in 2% of GAI N a dju ste d at 0 .1
Accuracy
V /div
U ncalib
r
ate
d Contin uously varia b le ; exte nd s de-
flection facto r to at least 50 V /div
GAI N
Permits adju stme n t of deflection
facto
r
at 0 .1
V/ d iv fo r
all
Oscillo-
scopes
F re q uency R espon se
(8
Divisio n R efe r ence)
Ba nd wid t h , Direct
Cou p led In p ut
FULL
M ode DC to 150 MHz with 7700-Se r ies
Oscillosco p e
DC to 90 MHz
wit h 7500-Series
Oscillosco p e
20 MHz M ode
DC to 20
MHz
wit h in 2 MHz
Ca p acitive Co up led 15 Hz
or less
L ower Frequency
-3 d BL imit
R isetime 2 .4 ns or less with
7700-Se r ies
Oscilloscope
3 .9 n s o r less with 7500-Se r ies
Oscilloscope
R iseti m e (6 Div 1 .40 n s or less 5
m V -20 V/ d iv with
R eference) 7904 oscilloscope
.

Specification-7A11
TA BLE 1-1 (co n
t)

TA
BLE 1-1 (cont)
Ch
aracteristic Performance Re q uireme n t
DC Drift
Drift With Time
(Ambient Tem p er-
ature and L ine V ol-
tage Constant)
Sh ort Term 0 .1
d ivision or less d uri n g any
1
minute
interval with in 1 h our after
20 minutes
f r om turn-on
L o ng Term
0 .3 division or less duri
n g
any
h our
after 20 minutes from turn-on
D r ift W it h Am
b ient
Tem p
erature change
( L ine V
oltage Constant)
Plug-in Only
200 μ V / ° C or less
P
ro
be
Only
200 μ V / ° C or less
Trace ID EN TI F Y 0 .2 to 0 .3
division u pward trace
s h ift
O FF S E T Range
5 m V / d iv t h ru
+1 V to -1 V
50 mV / d iv
0 .1 V / d iv t h ru
+20 V to -20 V
1 V /div
2 V /div th ru
+400 V to -400 V
20 V /div
O
FF
S
E TO U T
Ra
n
ge +1
V to -1 V (nominal)
Ratio of Offset
Range to O
FF S E T
O U T
5 m V /div t h
ru 1 :1 with in 1°/ ο p lus 0 .5 m V at O
FF-
50 mV / d iv
S E TOUT j ac k
0 .1 V /div
t h ru 20 :1 wit h in 1 .5% ο p l us 0 .5
m V at
1 V /div
O FF S E TOU T j ac k
2 V /div th ru 400 :1 with in
2% p lus 0 .5 mV at
20 V / d iv O
FF
SE
TO UT j ac k
Sou r ce
Resistance 500 Ω with in 3°/ ο
Ch a r acte r istic
P erforma n ce Re q uirement
M axim
u m I npu t V olt-
age Wit h or
Wit h out
AC Cou p ler
I n stalled
DC
+ P
ea
k AC 200 V ; AC com p one n t not to ex-
cee damplitude specified u
n
d er AC
AC, continuous
wave
5 m V
t h ru 200 V pea k to 50 kH
z ; see F ig . 1-2
50 mV for amplitu de de
r ating due to fre-
quencies above
50 kH z
0 .1 V
t
h
r u 200 V peak to 40 MHz ; see
F ig . 1-2
1
V for am p litude d erating
due to fre-
q uen cies a b ove 40 MH
z
2 V t h r u 200
V pea k to 70
MHz
; see F ig . 1-2
20 V for am p litude derati
ng d
ue
to
fre-
q uencies above 70 MH
z
DC, Ca p acitive 200 V
Cou p led (AC
Co u pler I n stalled)
In put R and C
Resistance 1 ΜΩ with in 1°/ ο
Cap acita n ce
5 m V / d iv t h ru A pp roximately
5 .8 pF
50 mV / d iv
0 .1 V / d
iv t h ru Approximately 3 .4 pF
1 V /div
2 V /div t h ru Approximately
2 .0 pF
20 V /div
M aximum
Gate 0 .25
ηΑ or less at 25 ° C,
increasing
Cu r re
n
t
to
1 .2 ηΑ or less at 50 ° C
N oise
(Tange n tially
0 .1 d ivisio n (maximum),
measure d
measure d in FULL
in 7000-Se r ies Oscillosco
pe
M o d e)

1000 ν
200 ν
100
V
P ea k
V oltage
10 V
1 ν
Η ΙιΗ
ω
Γ ' ΙΙΙ

Ι Ι ~ Ι

111111

Ι Ι
Ffl
MEN
FTI
ι ~
Ι ~ o """" ~~~
m
/
Ι ~/ """" ~~~ // "
ιιι
_
" ΕΕΜ MS """" ==
E UMMS
MOMS so on
σ
F ig . 1-2 .
TA
BLE 1-1 (cont)
F re quency vers u s maxim u m i npu t am p lit ud ed erati
n g
grap
h .
Specification-7A11
2 ηΑ
1 .5 ηΑ
1 πΑ
..
Εd
~ κυ
Ύ
0 .25
ηΑ
0 .1
ηΑ
X
Π
ιι
20 0 C 30 0 C
40 0 C
50 0 C
60 0 C
Pr ob e Am b ie n t Te m pe r at ur e
F ig . 1-3 .

7A 11 m axi m um gate c ur rent vers u s P ro be a mb ie n t te m -
pe r atu r e i n "non-stored" m od e . To d ete rm i n e maxi mu m gate
cur-
re n t wit h P ro be store d , a dd +11 ° C to P ro b e am b ient temp er at ur e .
C h aracteristic P erformance Re q uirement
50
Ω
Te
r mi nation/
Ada p ter
In p ut Im p edance 50 Ω wit h i n 1%
P owerR ating 1 W att
ENV I R O NMEN
TA L
P ro b e
Temperatu r
e
Non-operating -55 ° C to
+75
° C
O perating 0 ° C to
+65
° C
Altit ude
Non-operating To 50,000 feet
Operating To 15,000 feet
V ibratio n 15 minutes alo n g eac h axis
at 0 .025
inc h Ρ - Ρ d is p laceme n t (3 .9 g's
at
55 c/s) 10 to 55 to 10 ε/s in

Specification -7 Α 11
F ig . 1-4 . Sta nd ing wave r atio g r a ph s h owi ng a pp roximate V S WR w h ic h can b e expecte
d w he n t h
e
7 Α 11 Pr
ob e is
u
se
d wit h t h
e 5092
Termination/Adapter attac h e d .

TA BLE 1-1 (cont)
1 T he Plug-in en
vi r
o
nm en t is d e pe nd e n t upon t h e oscillosco pe . See
t h e e n vironme
n
tal specification
in t h e app lica b le oscillosco pe
m a n ual .
TA BLE 1-1 (co n t)
Specification-M1
C h aracte
r istic P erfo r mance R e qu ireme n t
P ro b eB ody Grey plastic h ousing
Dime n sio n s
Plug-in
-14 .58 inc h es' lo n g, 2 .75 i nch es
wid e, 4 .98 inc h es h ig h ; overall
P ro b e B ody -6 .53 inc h es long, 0 .63 i nch es
wi d e, 0 .66 i nc h es h ig h ; overall
P
robe Cable -8 .83 feet lo ng
W eig h t, Plug-In
and Pr obe com-
b ine d
N et -2 .75 p ou n d s
Sh i pp ing
-4
.5 p oun d s
C h aracteristic P erformance R equ i r ement
1-mi nute cycles . T h ree mi
n
utes
at
any reso nan t point or, if
n
o
n
e,
at
55 ε /s
S hock 400 g's, 1/2
sine
;
3 s hock s alo n g
eac
h
axis at
1/2 ms, 1 ms and2 ms
duration (total of
27 s h
oc
k s)
P l u g- Ιη 1
Altitu d e
Non-operating To 50,000 feet an d -55 ° C
PH YSICA L
F inis h
Plug-in Anodized
alumi n
um
front p anel

Ge n eral
S
E
CTIO
N
2
OPERATING I N
ST RU CTIO N S
Ch ange i n formation, if any, affecting
t h
is
section will
be found at t he r ea r of t he manual .
T
h
is
section co n tains an ex p lanation of external con trols
an d conn ectors
for t h
e Plug-in
Un it ( F ig . 2-1) a nd its
attac
hed P
ro
be
(
F ig . 2-2) . It also co n tai n san explan ation of
accessories, α fi r st-time o p erati ng p r oce dure and a dd itional
operati ng h ints . It is recomme nd e d t h at t h is sectio nb e rea d
in its entirety p rio r to normal usage of the 7A11 Plug-In
Un it a ndP ro be .
PLUG-IN I NS ER TIO N A ND REM O VA L
T h e 7 Α 11 is calib r ate d and r ea d y fo r use as received . It
can b e i n stalle d in any com p artment of 7000-Series oscillo-
sco p
es,
b ut is
inten de d for p ri n ci p al u
se
in vertical p lug-i n
com p artments .
To
i n stall, alig n t h e u pp er and lower rails of
t he 7 Α 11 with t he oscillosco p e t r ac k s and f u lly insert it .
T h e f r on t will be flus h with t h e f r ont of the oscillosco p e
w hen t he 7 Α 11 is fully inserte d , and t h e latc h at t h e
b ottom-left corner of the 7A11 will b e i n p lace agai n st t h e
fro n t p anel .
To remove t he 7A1 1, pull on t h e latc h (wh ic h is i n -
scri b ed with t he u nit ide n tificatio n "7 Α 11") and t he

7A11
will unlatc h . Co n ti nue pulli ng on t h e latc h to sli de t h e
7A11 out of the oscilloscope .
PR O BE REM OVA L A ND STO R AG E
To remove the Pr ob e : W it h t he

7A11 Amplifie r r e-
move
d from t h
e
oscillosco p e, locate t h
e
P ro b
ean
d Store d
P ro b e I nput A da p ter on t he r ig h t si d e of t h e 7 Α 11 ( F ig .
2-2 Α ) . M ove t he Pr ob e b ac k , d isco nn ecti ng it f r om t h e
A da p ter . N ote t h e plastic latc h (la b ele d PRE SS) on t he si d e
of t he A d a p ter ho u sing . Wh ile h ol d i ng t h is latc h d ep r esse d ,
move t he A d apte r out t hr oug h the front of t he 7A1 1, as i n
F ig . 2-2( Β
) .
Un coil the desi r ed n u m b er of t urn s of ca b le from t he
ca b le d rum an d re m ove t he P ro b e t h ro ugh t h e A d apte r
access h ole . Wh en t he P ro b e an d ca b le have b ee n remove d
fa r enoug h to ta ke up t he slac k ca b le wit h in t he 7A1 1, cli p
t he A d apter to the ca b le as s h own in F ig . 2-2(C) . T hen
insert the Stored P ro b e Inp u t A d a p ter into its hou si ng i n
t he 7A1 1, as i n F ig . 2-2(D) . R everse t h e proce dur e to r e-
i n stall the P ro be .
E XT ER N A L CO N T R O LS A N
D
CO
NNE CTO R S
Plug-in U nit
VO L TS/D 1 V
V
A R IA BLE
(CA
L IN)
P OSITIO N
ID EN TI F Y
O
FF
S
E
T
ON-OFF
COA R S E
7 ΑΙΙ 1
Α 12-p osition switc h graduate
d
from 5 mV t h ro ugh 20 V
i n
5-10-20 se q uence . In ad d
itio n to
se-
lecting cali br ate
d d eflectio n facto r s,
it i nd icates t
h
e
in pu t ca p acitance
and offset
voltage r ange a p plica b le
to eac h switc h p ositio
n .
Com b i n ation switc
han d pote n tio-
meter .
Wh
e
n t he control is i n its i n -
w ar d p ositio n , deflection facto r s
a r e as in d icated b y t he V O L TS/DI V
switc h . P us han d release kn ob to
e n able
selection of un calibrate d d e-
flection facto rs b etween the val ue
i nd icate d by t h e VO L TS/DI V
switc h an d at least 2 .5 times
t
h at
val ue .
M oves d isplay
vertically
on
C R T
w
hen
Plug-in U
nit is i n vertical
com p artment of oscil
l
osco
p
e .
P er-
mits
h
o
r
izo n
tal
moveme
n t of dis-
play w h en Plug-in
is i n h orizo n tal
p
lug-i n com
p artment of oscillo-
scope .
L ocate
d in
ce
n te r of P OSITIO N
kn o b . Wh en pushed, causes approx-
imately
1/4
d ivisio
n moveme n t of
display .
Oscillosco p es equ i p ped
with rea d o u t simulta n eously dis
play
t he word "ID EN TI F Y" in t he
7A11
rea d ou t area on t he CR T .
P ermits or in h i b its op eration of the
O FF S E T co n tr ol .
Outer of two concentric k no b s .
Sto p -to-sto p r otation in j ects offset
voltage eq
uivalent to +1 t h
roug
h
-1, +20 t h roug h -20, or +400
t hr ou gh -400 volts at t he i npu ts,
de p e nd ing upon positio n of

Operating
Instructions-7A11
COA R SE
(cont .)
Fig . 2-1 . 7A 11
F ro n t P an el .
2-2
FI NE
POLARITY
+ UP
V O L TS/DI V switc h . Countercloc k -
wise p osition offsets
t h
e
in p ut wit h
α negative voltage, cloc k wise p osi-
tio n offsets t h
e
input with α p osi-
tive voltage .
Inner of two concentric k nobs . One
revolution in j ects an e q uivalent of
app roximately 0 .4, 4, or 40 volts
offset voltage, dependent upon po-
sition of VO L TS/DI V switc h
.
Selects up ward deflection
for
positive-going inp ut signals . If t he
7A11 is used in α h orizo n tal p lug-in
com partmen t, selects rig ht deflec-
tion for p ositive-going signal .
I NVER T
BA N D W IDT H
FULL
20 MH z
ST EP ΑΤΤΕΝ BA L
O FF S ET O UT
GAI N
STO RE D PR O BE
I NPU T
R elease L atc h
Selects dow n war d d eflection for
positive-going input signal . If t he
7A11 is b eing use d in α
h orizontal
p
lug-in
compartment, selects left
deflection for positive-going i nput
signal . U pwar d (or rig h t)
deflection
for positive going i
nput signals is
p rovided if bot h
switc h es are i n t h e
outward
position .
P rovi d es full b andwi d t h as s p
ecifie d
for 7 Α 11-oscilloscope com
b i n ation .
R e d uces upper fre q uency -3
dB
limit of 7A1 1 -oscilloscope to 20
MH
z . Full b andwi d t h is p rovide
d if
both switc h es are in t he outward
position .
E xternally b alances circuitry to
avoi
dsh ifting of no-signal trace
w
h
en
VO L TS/DI V switc h positio n
is
ch ange d .
Miniature p h o n e j ac k , ma k ing selec-
te
d value of offset voltage available
externally . No outp ut p rovi
d
e
d
w hen O FF SE T switc h is O
FF .
Screw d river ad j
ustment permitting
external
cali b ration of VO L TS/
DI V . Normally ad j uste d wit h
VO L TS/DI V at .1 p osition as indi-
cated by t he s h ade d area
surroun d -
i ng t he .1
at t h e VO L TS/DI V
switc h
.
BN C j ac k connected to Probe ti p
w hen P robe is store d with in 7A11
Amplifier .
Note
t
h at value of capac
itance

indicated

at

VO L TS/DI V
switc h must be increase d by 1 .2 pF
w hen t h e STO RE D PR O BE I NPU T
A d apter is use d . Wh en P robe is
with drawn from 7 Α 11 Am p lifier,
STO RE D PR O BE I NPU T is usually
d isconnecte
d from t he circuit
.
Max-
imum allowable DC p lus pea k AC
i nput voltage is 200 volts . Consult
specification section for derati n g
d ue to fre q uency .
L atc h inscribed with p lug-in i d enti-
ficatio n "7 Α 11" . Pull k nob to re-
lease
latc h w h en removing 7 Α 11
from oscillosco p e .

F ig . 2-2 . Pro b
e sto
r
age a nd re m oval .
O p erating Inst r u ctions-7 ΑΙ 7
2- 3

Ope r ating Instructions-7A11
P robe
Tip
2- 4
AC Co up le r , R et r acta b
le H oo k Ti p a n d
t h r ee i n c h Gro u n d
i n g L ead installe d
M iniature
type, DC-coupled to in-
ternal circuitry . Can be e q uipped
wit h DC bloc k ing ca p acitor (see
Accessory Information) . Can also
be e q ui pp e d with p i n c h er ti p or
h oo k ti p for attac h ing
P
robe to
cir-
cuitry . M aximum allowable
DC +
p eak AC in p ut is 200 volts .
Consult
specification section for d erating
d ue to fre q uency .
F ig . 2-3 . (
Α
) Accesso
r
ies ; (
Β ) Accessories i n stalled .
ID EN TI
F Y
p us h button
Groun d Contact
Nose Groun
d i n g L ea d and AC Co
up le r
i n stalle
d
Pr
o
be co nn ected
to
50
S? Terminatio n
Ada
p te r
Depressing it causes approximately
1/4 d ivision trace sh ift . Also causes
the word "ID EN TI F Y" to appear
in 7 Α 11 rea d out area on CR
T if
oscillosco p e is e q ui p pe d wit h read-
out circuitry .
F
emale-t
h reade d co n tact for attac h -
ing grounding lea d .

ACC E SSO R I ES I NF O RM ATIO N
Accessories a r e su pp lie d with t he Pro b e to exten d its
ope r ati ng ca p abilities . T h ese accesso r ies a r e shown in F ig .
2-3 a nd are i n ten d e d to b e u tilize d as follows :
1 .
AC
Co u ple r . Slip-on ty p e contai n i ng α .015 μF capac-
itor . B loc k s
DC from Probe
.
H
as a 15 Hz low-frequency
-3
dB poi n t . A dd s 2 .4
pF to in pu t
ca p
acitance in d icate d at
VO L TS/DI V
switc h .
2 . R et r actable
H oo k Ti p . Slip-on ty p e for use with or
with o ut AC Co
up le r . A dd s ad ditio n al 1 pF i np ut ca p aci-
ta n ce . H oo k Tip b ody
moves toward rear of P ro b e to ex-
pose h oo k . Contai n s female-t
h readed gro und con nectio n
fo r use with eithe r α
3 inc ho r 12 i nch screw-in g r oun d lead .
3 . H oo k Tip . Slip-on
device for use with or wit hout AC
Cou p le r .
4 . Ins u lati ng T ub e . Slip-on d evice for i n sulati ng grou n d
su r face
at Pr o b
e
ti p or AC Co u pler ti p .
5 . B ayo n et G r o und . Slip-on d evice fo
r
use
wit h or wit h -
ou t AC Cou p ler . Sp r ing loa ded con
tact permits com p leti ng
t he Pr ob e g r ound circuit imme
d iately ad j acent to Pr o be
sig n al i nput ti p .
6 . G r oun d i ng L ead,
Nose . Slip-on d evice w h ic h ma k es
con tact wit
h gro un d surface at Pr ob e or AC Co up ler tip .
Ot
h
e
r en d e qu i pp ed wit h 6-32 male
t hr
ea
d for attac h m en t
to
alligator cli p .
7 . G r ou nd i ng L ead, Screw-in, 3 i nc h .
Primarily for u se
with R etracta b le H ook Tip . T h rea
d
e
d b ot h end s . O n e en d
to be attac h ed to R
etracta b le Hoo k Ti p , othe r en d fo r use
wit h alligato r clip .
8 . G
r
ou
nd ing L ea d , Screw-in, 12 i n c h . T h rea ded b
ot h
e n ds .
F or u se betwee n th r ea d ed female grounding
contact
at
Probe and alligator clip . Can also b e attac
hed b etween
gro und i ng female th r ea d at R et r acta b le H oo k Tip and
alli-
gator cli p .
10 . 50 Ω
Termination/Ada p ter, G R -to- probe ti p . Ca n
be used in any
situatio n re q uiring 50 Ω pr o be input im p e d -
ance .
11 . Ca b le Assem b ly . Eq uipped wit h min iat
u
re
telep h one-
j ac k plug, coaxial ca b le, and alligato r cli p s .
F
or
use
wit h
O
FF SE TOU T j ac k .
9 . Alligato r Cli p
s . F or use wit h grou n ding leads .
Ge ne r al
O p eratio n of the 7 Α 11 Am plifie r a nd Pr o be i nα vertical
p lug-i n com p a r tme n t of an oscilloscope is explai n ed h e r e .
Operatio n of the unit wit h t he Pr ob e stored is ex p lained
first . T h is is followe d by α description of operation wit h t h e
Pr obe and its accesso r ies .
P reliminary
Install the

7A11 Amplifier i n to α vertical com p artme n t
of α 7000-Se r ies oscilloscope e qu i ppe d wit h α time-base
u nit . Set t he equ ipme n t con t r ols as liste d in Ta b le 2-1 .
F I R ST TIME O PER ATIO N
TA BLE 2-1
Preliminary Co n t r ol Setti n gs
ST EP ΑΤΤΕΝ B A L A d j ustment
Operati ng Instructions -7 Α 11
1 . U si ng the 7 Α 11 POSITIO N control, set t he t r ace to
ve r tical center of the g r atic u le . T h en d ep r ess the I NVER T
b u tton an dn ote the t r ace p ositio n .
2 . U si ng the STEP
ΑΤΤΕΝ B A L con t r ol, move t he trace
to α p oint mi d way between its pr ese n t p ositio na nd t he
vertical ce n te r of t h e g r aticule .
3 . Agai n u si ng the POSITIO N co n t r ol, set the trace to
graticule ce n te r . T h en de pr ess the + UP b utton and again
note the t r ace p ositio n . It s h oul d h ave r emained at g r aticule
cente r . If n ot, agai n ad j ust STEP ΑΤΤΕΝ BA L to p ositio n
t h e trace mid way b etwee n its pr ese n t positio n and graticule
ve r tical ce n te r .
2-5
7 Α 11 Am p lifie r
VO L TS/D 1 V .1
POSITIO NM i d range
O FF S E T O FF
POLARITY +UP
BA ND W IDT H FULL
Time Base
T r igge r i ng
M o de A u to
Co up li ng AC
So u rce I n t
M ag n ifie r Χ 1
Ti m e/Div 1 ms
V aria b le Cali b rate d
Oscillosco p e
Intensity an d F oc u s A dju sted fo r O p timum Trace
Beam
F
i nde
r N
o
r mal
Cali br ato r .4 V
R ate 1 kH z

Ope r ating Instructions-7A11
4 . Repeat t h is p roce du re u ntil no tr ace s h ift accompa-
n ies switc h i ng betwee n
+
UP an d I NVER T .
5 . C h ec k ST EP ΑΤΤΕΝ B A L a dj ustme n t b y rotating the
V O L TS/DI V switc h t h ro ugh all p ositions a nd noting t h at
no trace s h ift occurs .
6 . T he ST EP ΑΤΤΕΝ BA L ad j ustment s h ou l d b e r e-
ch ec k ed eac h time t he 7 Α 11 is use d . Do n ot use t he ST EP
ΑΤΤΕΝ B A L a dj ustme n t as α positio n con tr ol .
ID EN TI F Y
1 . De p ress t he

7A11 ID EN TI F Y button w h ile o b serving
the tr ace . Note t h at t he t r ace s h ifts u pward a pp roximately
1/4 d ivisio n w h en t he button is pu s he d , and returns to
its
p r evio us position w hen t he bu tto
n
is
r
eleased .
2 . If t h e oscilloscope is equip p edwit h r eadout circ u itry,
note t h at t h e wor d "ID EN TI F Y" appea rs in the 7A11 rea d -
out area of t he CR Tw h ile t he ID EN TI F Y b utto n is p us h ed .
T he d eflection factor in use s h oul d a pp ear i n t he readout
area w h en t he ID EN TI F Y b utto n is released .
B A N D W IDT H
1 . Ad j ust t he oscillosco p e Inte n sity andFocus controls
to o b tai n optimum trace s ha r pness .
2 . Dep r ess the FULL B andwidt h switc h and note t h at
the t r ace b ecomes slig h tly less clearly d efine d . T h is occ ur s
b ecause α muc h wide r fre q uency range is now b ei ng dis-
played, an d t he total noise i nc r eases accor d i n gly .
Α b etter in d ication of bandwi d t h operatio n can b e ob -
tai ned by connecting t h e out p ut fr om α h ig h -fre q uency gen-
erato r to t h e STO RE D PR O BE I NPU T . W it h 20 MHz
applied from the sig n al generator, an d FULL selecte d at
7A1 1, a dju st for 5 divisions of vertical d isplay . T h en select
20 MHz at t h e 7A11 and note t h at t he vertical amplitude
dec r eases to a pp roximately 3 .5 d ivisio n s .
GAI N
1 . Co nn ect α 50 Ω coaxial ca b le betwee n t he
STO
RE
D
PR O BE I NPU T and t he Cali b rator o
u
t p
ut
j
ac k at t he
oscilloscope .
2 . Note th
at with 0 .4 V an d 1 kH z selecte d
at
t he Cali-
brato
ra nd .1 V
O L
TS/DI V selected at t he
7A1 1,
α d isplay
of ap proximately 4 d ivisions app ears on t he C RT .
2-6
A dju sti ng t he GAI N control wit h t h e oscilloscope Cali-
br ator signal app lie d p rovi d es a b solute acc u racy to with i n
2% i n t he ad j uste d p osition at tem p eratu r es b etwee n 0° C
and50 ° C . Ot h er deflection factors will t hen b e acc u rate to
with i n 4°/ ο absolute between 0
°
C an
d50 °
C .
If g r eater
gain accu r acy is r e qu i r e d , α more accurate
amplit
ude
cali
br ato r must be used and all inst ru me n ts m u st
b
e
r estricted to α tempe r atu r e ra n ge of 15 ° C to 35 ° C . T he
Te k tronix Amplitu d e Calibrato r an d Com p arator, P art No .
067-0502-01 is r ecommen ded for t h is pu rpose . An ab sol u te
acc ur acy app r oac h ing 2% may t h en b e o b tai n e d ove r t h e
ra
n
ge of
d eflection factors .
P
O
L A R ITY
1 . Disconnect t he coaxial cable f r om t h e STO RE D
PR O
BE I NPU T A d ap ter . T hen a d j ust the 7 Α 11 POSI-
TION co
n t r ol as n ecessary to p lace t h e trace at g r atic u le
vertical ce
n
te
r .
2 . Re-connect t h e coaxial ca b le to t h e STO RE D PR O BE
I NPU TA d apter and note t h at t h e 1 kH
zs
q uare wave is
displayed in αp ositive o r u p wa r d d i r ectio n from t h e refer-
ence position esta b lis he d at g r aticule ce n ter .
3 . At the 7A1 1, depress t h e I NVER T button . N ote t h at
now the p ositive-going s q uare wave is deflected in α down-
wa rd d i r ectio n on t he C R T .
4 . De p ress t h e + UP b utto n to r egain upward deflection
of t h e p ositive-going s qu a r e wave .
O FF S ET
1 . A dju st t he outer O FF S ET kno b as necessary to place
its w h ite mar k er at 0 .
2 . Depress t he O
FF
S
E
T ON button . T he trace may s h ift
up war d or downward .
3 . M ove t h e O
FF
SE T controls an d note trace reactio n .
Clock wise moveme
n t
ca
u
ses
up
ward deflectio
n ,
w h ile
coun
tercloc
k wise movement ca u ses d ow n war d d eflectio n .
Also n ote t h at t h
e
F I NE con trol kno b
ca
u ses
con
si de ra b ly
less reaction t h a
n t
he COA
R
S
E
con
tr
ol kn ob . (T he two
kno b s h ave α
r
atio of a pp roximately 10 :1 .)
4 . Dep r ess t he O FF SE TO FF bu tton . T he s qu are wave
d isplay s hou l d now a pp ear in t he u pp er h
alf
of t he CR T .
Ο

5 . Switch t he oscilloscope Cali b rator to 4 V an d note
t h at t he up p e r exc u rsions of t he s qu are wave are no longe r
visible . If it is d esi r ed to d isplay t he uppe r po r tio n s of t h e
s q uare wave, pull out on the oscillosco pe BEAM F I ND ER
k no b , causing the en ti r ed isplay to appea r on t he CR T .
6 . De p
ress t h
e O
FF
SE
T
ON
bu tto n and a dj ust t he
O
FF-
S ET control
as
n
ecessa
r y to place t heto p of t he s q
uare
waves at graticule center .
7 . Return t he BEAM F I ND ER to n ormal b y dep ressing
and r eleasi ng t h e b u tto n . N ote t h at the u ppe r portio n of
t he s q uare wave now a pp ears near graticule center . Refine
t he O FF S ET ad j ustme n t (if n ecessary) to alig n t he to p s of
t he square waves with t he graticule ve r tical center .
8 .
Calculate t he O FF S ET voltage b ei ng a pp lie d . It is
eq ual to t he O FF SE T d ecimal val ue (in d icate d by
the O FF-
S ET knob) multi p lie d b y the O
FF
SE
T RA NG E (indicate d
by the V O L TS/DI V switc
h ) . In t h is case, the calculatio n is
- .2 Χ 20 V = -4 V . (-4 volts is
n
eeded
to retu rn α +4 V
signal to graticule center .)
9 . U si ng α DC voltmeter and t he Cable Assembly, c h ec k
t h e voltage available at t h e O FF S E TOUT j ac k . It is eq ual
to t h e value indicate d b y t he O FF S E T kno b , a nd can never
exceed a pp roximately ±1 V . N ote t h at only 0 .2 V is p r ese n t
t h ere, eve n t h oug h t h e offset voltage b ei ng applie d to offset
t h e incoming sig n al is eq uivale n t to 4 V .
10 . T u r n t h e O FF S E T button O FF an d disconnect t h e
coaxial ca b le fr om the oscilloscope an d t he STO RE D
PR O BE I NPU TA d a p ter .
P robe O p eration
1 . Pull out on t h e

7A11 L ock i ng L atc h and remove t he
7A11 from the oscilloscope p lug-i n un it compa r tme n t .
2 . L ay t h e

7A11 on its left si d e and remove t h e P robe as
ex p lai ne d i n t he begi nn i ng of t h is sectio n . Replace t h e
7 Α 11 in t he oscillosco p e p lug-in compartme n t . Allow
approxi
m ately
1 mi
nu
te to elapse b efore continuing wit h
t hep
roce du re .
3 . De p ress t he ID EN TI F Y b utto n n ear t he r ea r of the
P robe b ody and note t h at t h e trace moves approximately
1/4 d ivision j ust as it d i d w hen t h e front panel ID EN TI F Y
bu tto n
was
de pr esse d . If t he oscilloscope
is equi
pp
ed with
readout circuitry, also n otice t h at t h e word "ID EN TI F Y"
appears i n the

7A11 readout a r ea of t he C R T .
4 . Switc h t h e oscillosco pe Calibrator to 0 .4 V . Now
to uch t h e Pr obe tip to t h e Cali b rator outp ut j ac k cen te r
termi n al a nd n ote that approximately 4 divisions of s qua r e
wave a pp ears on the up p er h alf of t h e C R T .
Ope r ating Instructions-7A11
5 . Disconnect t he P ro be from t he j ac k . Attach t he AC
Cou p ler accesso r y to t he Pr obe ti p . Connect t he Coup ler tip
to t he Cali b rator j ac k and n ote t h at t he 4 d ivision s q uare-
wave d is p lay now stra d dles the ve r tical ce n te r of t he g r ati-
cule, si n ce t he cap acitor i n t h e AC Coupler b loc k s t he DC
compo nen t .
6 . It is s u ggeste d t h at t he P ro b e's ot he r accessories b e
experimente d with at t h is time for familiarization pu r p oses .
Note th at w hen t he Retracta b le H oo k Ti p is installe d on
eit h er t h eProbe or the AC Cou p ler ti p , t he h ook can b e
exp osed by pulli ng b ac k on the r etracti ng tab . Also n ote
t h at eit h er the 3-i nch o r 12-i nc h screw-i n grounding lead
can be used with t he AC Coupler ti p . An alligator cli p
s h ould be attac hed to the opp osite end of t he g r ou n di ng
lea d s for attac h ing to convenient g r ou n de d su r faces .
7 . Remove the 7 Α 11 from t he
plug-in compartment .
Dep r ess t h e tab on t he si de of the
STO RE D PR O BE I NPU T
A d ap ter and remove t h e Ada p te r t hrough
t he f r o n t of t he
7A1 1 . Retract t h e cable i n to the
7A11 and wind it on t he
cable spool as necessary to d r aw t he Pr ob e t h
roug
h
t he
7 Α 11 f r o n t p anel . Sn ap t h e STO RE D PR O BE I NPU T
Ada p ter i n to place an d inse r t t he Probe i n to t he bac k of t he
Ada p ter . T he 7 Α 11 is agai n rea d y fo r
use i
n t
he sto
r e
d
p r obe mo d e .
U nscale d Deflection
F
actors
On
occasio n , it may be conve n
ie
n t to esta b lis h
ve
r tical
d eflection factors ot h er t han t h ose w h ic h are p r ovi d ed b y
specific positions of the V O L TS/DI V switc h . F or exam p le,
assume that
0
.8
volts/ d ivisio nd
eflection factor is desired . If
α 4-volt sq u a r e wave cali b rator sig n
al is a p plie
d
to α vertical
un it h avi n g 0
.8
volts d eflectio n
factor, t
he
dis p laye
d sig n
al
amplit u d
e
is e qu al to the applie d sig n
al
(4
volts) d
ivi de dby
t he d eflection factor, (0 .8 volts) w h ic h is eq ual to 5 divi-
sio n s of d is p lay . W it h t h is in mi nd , set the V O L TS/DI V to
t h
e
n ext lowe r d eflectio n facto r (i
n
t h
is case, .5
volts)
and
apply α
4-volt signal from t he
oscillosco p e Cali b rator to
t he
7 Α 11 Pr o be i np
ut
. T hen de
p ress and release t he V A R
I-
A
BLE
knob a
nd a dju st it
as
n
ecessary to o
b
tain 5 d ivisions
of deflection .
Α
0 .8
volt/ d ivision
deflection facto
r
now
is
in
effect .
It s h oul d b e n oted t h at
t
h
e same r atio of act u al d eflec-
tio n factor to V O L TS/DI V
switc h value exists in all oth er
switc h positio n s . T hu s if t he V A R
IA BLE control is i n t h e
p osition esta b lis hed in the p
rece
d
ing pa r agra ph a nd t he
V O L TS/DI V switc h is
placed
i n t
h e 2 V O L TS/DI V p osi-
tio n ,
α3 .2 volts/ d ivision d eflection factor
will be in effect
(0 .8 is to 0 .5 as
3 .2 is to 2) .
2-7

Op e r ati n g
Instructions-M1
Input Ca p acitance
Th e
i
np ut ca
p acita n ce of t h e 7A 11 Amplifier and P ro be
h as b ee n
d esigne d to be extremely low . Fo r exam p le, in t he
5 t hr oug
h
50
m V positions, i nput capacitance is 5 .8 p F . In
t
he .1
t hroug h 1 V p ositio n it is 3 .4 p F, and it is 2 .0 pF in
t he2 t h ro ug h 20 V p ositions . T h ese figu r es pertain w
h
en
t he P ro b e is connecte d d irectly to α circuit an d
m u st b
e
2-8
m odifie d wh en eve r ot h er cou p li n g co n nectors are used . T he
AC Couple r d evice ad d s 2 .4 pF . T he R et r acta b le H oo k Ti p
ad ds 1 pF and the STO RE D PR O BE I NPU T Ada p ter adds
1 .2 p F . Any ad d itio n al d evices s uch as co nn ectors or cables
between t h e sig n al source an d t he Pr o b e or STO RE D
PR O BE I NPU T con n ecto rs will f ur t h e r inc r ease i n put cap-
acitance .

General
S
E CTIO N 3
CIRCUIT
DESCRIPTION
Ch ange
information, if any, affecting t h is section will b e fo und at t h e rear of t h e manual .
T he d escri p tio n s contained in
t h is sectio n are refere nced
to t he sc h ematics containe
d in the b ac k of t h is manual .
A dd itional diagrams ap p ear wit h
t he text as necessary to
facilitate ex p lanations . T he sc
h ematic diagrams are coded
wit h n um b ers con taine
d in diamon d s haped o u tli n es . T h ese
nu m b ers are use d extensively on the sc
h ematics fo r c r oss-
referenci ng .
BL OC K DIAG RA M D
E
SC R
I P TIO N
R efer to F ig . 3-1 .
M
a j or com pon
ents of t he

7A11 Am p li-
fier are t he P robe, t he I
np
ut Am p lifier,
t
he
Out
p
ut
Am p li-
F ig . 3- 1 . 7A 11 b loc k diagram .
7 Α 11
fier, t he Offset
Generator an d t he R eadout Co n trol . Wh enα
signal is a pp lie d to
t
h e p
robe tip, α si n gle-e nded signal
p asses from t heP robe to
t
he Inp
u t Am p lifier, w h ere it is
converted to α push-pull
signal . It is t hen a pp lie dto t h e
Out p ut Am p lifier, w h ere it is am
p lified an d sent t h roug h
t h e interconnecti ng p lug to t he
oscillosco pe . T he Out p ut
Am p lifier also provi d es α push-pull
trigge r signal to t he
oscillosco p e for time b ase triggering
p
ur
p
oses .
An
Offset Ge
n erator p ermits app lication of α DC offset
voltage to
t
he
I np
ut
Am p lifie r , t h us enabling t he viewing of
AC signal compo nen ts in
t
hep resence of
DC at α muc h
h ig h er sen sitivity t han wo u l d ot h erwise
b e p ossible . Α
ID EN TI F Y
Probe O
1
ί "
(

Pr obe Atte nu ator
Switching
Offset V oltage
Sig nal
O FF S E T
O U T
Plug-in Un it
Offset
Ge ne r ator
4
[ON O FF
O FF S E T
ST EP ΑΤΤΕΝ
B A L
In pu t
Amplifier
2
B A N D W IDT H POSITIO N
r

1-1 -

-
I
NVER T
P
O L A
RITY
Uh I A L
L
VA R IA
BLE
Deflection F
actor)
R ea d out
Encoder
ID EN TI F Y
Ι VO L TS/DI V
- V OL TS/DI V Switc h and R ea dou t
5
R
ea do u t
Data
-
Ί
+ Signal
O
ut pu t
Push-Pull
Sig n als
Amplifier
3 - Signal
+
Trigger
ID EN TI F Y
-
Trigger
Signal