Tektronix 7a15 User manual

1 Ν
E3-rFt U CT1C> Μ
ΜΑΝ
V
A L
Se
r
ial Nu m ber
Tektronix, Inc . " Ρ . Ο .
Box
500 " B
eave
r
ton, O r egon 97005 " Ph
o
n
eό
44-0161 "
Ca
b les : Te k tr onix
070-1044-00

670

WARRANTY
All
Tekt r
onix ίη 5tr ιι r η eη t5 are war r a
n
te
d
against-
defective
m
ateriais and workmanship
for one year,
Tektronix
'transfo r
m ers, manufactured
in' o u
r
plant,
are wa r rante d f or
t h e life of the
instrument,
Any
μιι estions
wit h respect to t h e
warranty,
mentioned above -s
h oul d - be ta k
e
n
up'' with your
Tektronix F iel
d Cnginee ι o r Repre'sentativ? .
All
r equests
for re p ai r s and r eplace n ι ent p arts
should
b e di
r ected to t h e Te k t ro n i x Fiel d
Office or
repr esentative
in your area,' This p roce du re
w
ill
assure
yo u
the
fastest
possible ser v ice . P lease include the
instrument Type (or
P
art R lτι r r i b er3 - αη dSer i al
o
r
M o d el
Number ινίΙ h all requests for
parts
or
service .
S p eci f icatio n s an d p rice change
privileges reserve d .
Copyrig h
t 0 1970 by Te k tro n ix, I nc ., B
ea v ertoη , -
O r egon .
Printed . i n t h e U nite d States of America .
All
rig h
ts rese rve d . Contents of t h is
publication
may n ot
be reprod u
ce
d i n
any form-without permiss i on of t h e
co p yrig h t owner :, :. ", .

TABLE OF
CONTENTS
Page

Page
SECTION 1

SPECIFICATION

SECTION
5

PERFORMANCE CHECK/CALIBRATION
Introduction

1-1

Introduction

5-1
Electrical Characteristics

1-1

Test Equipment
Required

5-1
Environmental Characteristics

1-2

Short-Form Procedure
and Index

5-2
Physical Characteristics

1-2

Performance Check/Calibration
Procedure

5-4
SECTION 2

OPERATING INSTRUCTIONS
General

2-1

SECTION 6

ELECTRICAL PARTS LIST
Installation

2-1

Abbreviations and Symbols
Front-Panel Controls

2-1

Parts Ordering Information
First Time Operation

2-1

Index of Electrical Parts List
Control Setup Chart

2-2
General Operating Information

2-4
Basic
Applications

2-5

SECTION 7

DIAGRAMS AND MECHANICAL PARTS
ILLUSTRATIONS
SECTION 3

CIRCUIT
DESCRIPTION
Introduction

3-1
Block Diagram
Description

3-1
Detailed Circuit Description

3-1
SECTION 4

MAINTENANCE
Introduction

4-1
Preventive Maintenance

4-1
Troubleshooting

4-2
Corrective Maintenance

4-5
Instrument Repackaging

4-8
Mechanical Parts Illustrations
Instrument Repackaging
SECTION
8

MECHANICAL PARTS LIST
CHANGE INFORMATION
Mechanical Parts List Information
Index
of Mechanical Parts Illustrations
Mechanical Parts List
Accessories
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 .

7
Α 15

Intro d uction

TABLE 1-1 (cost)
The 7
Α 15 vertical amplifier p lug-in unit is d esigne d for
u se with Tektronix
7000-series Oscillosco p es . The

7A15 is α

Characteristic

Performance
wi d eband general purpose
am p lifier, with t he upper fre-

Freq uency R esponse

7500-series

7700-series
q uency limit d
etermine d mainly by the oscillosco p e
in

System De pend ent

Oscillosco
pe

Oscillosco p e
which it is u se d . For exam
p le, the 7 Α 15 use d with t he 7504

Up p
er Ban dwidth

60 MHz

75 MHz
oscilloscope will h ave αSystem
Ban dwidth of 60 mega-
hertz ;
an d when use d with t he
7704 oscilloscope, the

(DC Coupled)
system
bandwidth will be 75 megahertz . Α P OLARITY

Lower
Bandwi d th
switch
provides α means
of inverting the d is p lay . The 7 Α 15
can be operate
d
in any p lug-in com partment of the 7000-

(AC Cou p le d )
series oscilloscopes .

W
ithout
P
robe

2
h ertz or less
This instrument will meet the
electrical characteristics
listed in Table 1-1 following
complete calibration as given
in
Section 5 . The p erformance
check proce d ure given in
Section
5p rovi d es α convenient method
of checking instru-
ment p
erformance without making internal
ad justments .
SECTION 1
S PE
CI
F I
CA ΤΙΟΝ
Ch ange
information, if any, affecting t h is section
will
be found at t h e rear of t he man u al .
The following
electrical characteristics are valid over
the

Capacitance

20 picofara d s within 1 .5 p icofarad
state d environmental range
for instruments calibrate d
at an
ambient tem p erature of
+2 ρ° ς
to
+30°C,
and after α
five

R
an d CP roduct

W ithin 1°/ ο over all d eflection factor
minute warmup unless otherwise
noted .

settings
Deflection
Factor
Calibrate d R ange
GAIN
C
h aracteristic
Gain R atio
Accuracy
Uncalibrate
d
(Variable)
TABLE 1-1
ELECTRICAL C HARACTERISTICS
P erformance
5 mV/ d iv to 5 V/d iv ; 10 ste p s in α
1, 2, 5 se q uence .
W ithin 2% of GAIN ad juste d at 10
mV/ d iv .
W ith Ρ 6053 P robe
Ι
0 .2 h ertz or less
Maximum Input

500 V (DC + Peak AC) .
AC com-
Voltage

I
p onent 1 kHz or less .
In p ut R an d C
R esistance

1 1 megohm within 2°/
ο
7 Α 15
Maximum Input

0 .5 nanoam p ere or less, 0 ° C to
Gate Current

~
+35°C .
2 nanoam p ere or less, +35 ° C to
+50 ° C .
Displaye dN oise

0
.06
division
or less at 5
mV/
d iv
(Tangentially

measure d in 7700-series oscillo-
Measured) scope .
DC Drift
Drift
W ith Time
(Ambient Tem-
perature and
Line Voltage
Constant)
Continuously variable b etween cali-
brated ste p s ; exten d s d eflection
factor
to at least 12 .5 V/ d iv .
Short
Term

250

microvolts/minute

(P-P)

or
P ermits a
d justment of d eflection

0 .05 d ivision (whichever is greater)
factor
for
all 7000-series oscillo-

in
any one minute, after one h our
sco p es .

warmu p .

Specification-7A15
Characteristic
Long Term
Drift With
Ambient Tem-
perature (Line
Voltage Constant
TABLE 1-1 (cont)

TABLE 1-2
ENVIRONMENTAL CHARACTERISTICS
Performance
250 microvolts/hour (P-P) or 0 .05
division (whichever is greater) in
any one
hour, after one hour
warmup .
Refer to the Specification for the associated oscilloscope .
100 microvolt/degree centigrade or

TABLE 1-3
less .

PHYSICAL
Fits all 7000-series plug-in compartments .

SECTION 2
OPERATING
I NSTRU CTIO N S
Ch ange information, if any,
affecting this section will b e found at t h e rear of
this
manual .
General

ID EN TI F Y

Wh en p
resse d , d eflects trace up-
The 7 Α 15 vertical p l u g-i n units o p erates with α Te k -

war d for i d
entification andc h anges
tro n ix
7000-series oscillosco p
e
and
α7Β __
series time- b ase

CRT

rea d out

to

t he

word
u nit to form αcomplete oscillosco pe system .
To
effectively

"ID EN TI F Y" .
u se t he 7 Α 15, t h e op eration an d ca pab ilities
of t
h e instru-
ment s h o u l d b e k nown . T h is section d escribes th e o p eration

P O L A R ITY
of t he front-panel controls, gives first-time op eration and
general o p erating information, and lists some measurement

+
UP

Α ρο p itive- ce s α signal
at t he IN-
PU T

ro du s

p ositive d
eflection
tec h ni q ues using t he am p lifie r .

on t he CRT .
Installat i on

INVER
T

Inverts d is p lay . Α negative-going
The 7 Α 15 is d esigne d to operate in α vertical plug-in

signal at t h e IN PU T pr odu
ces α
compartment of Te k tronix 7000-series oscillosco p es . F or

positive d eflection on t he CRT .
Χ -
Υ
o p eration, t h e 7 Α 15 may also be installe d in α h orizo n -
tal
p
lug-in com p artment (refer to th e Oscilloscope Instruc-

CO
UPL I NG
tion Manual for i n formation on Χ - Υ op eration) . To install

AC

Ca p acitively cou p les t he in p ut sig-
t
he 7
Α 15 into α plug-in compartment, p us h it i n u ntil it is

ηαΙ to t he vertical am p lifier .
seated flus h against t he front p anel of the oscillosco p e .
To
remove, pull the release latc h to d isengage t he 7 Α 15 from

GND

Disconnects the in p ut
signal fr o m
t h e oscillosco
p
e .
Continue to pull t he release latc h to re-

t he am p lifier andground s t he
am
move
t he u nit from t he oscillosco pe .

p
lifier

in p ut .

Allows

the

in p
ut
coupling ca p acitor to be ch arged to
t he DC voltage app lied to the IN-
FRONT P A NEL CO NT R O LS

PU T conn ector .
All co n trols re qu ire d for operation of t he 7 Α 15 are lo-

DC

T he signal is
directly cou p le d to t he
cate d on t h e front panel of t h e unit . Α brief d esc r i p tio n of

am p lifier .
t he function or op eration of t he front p anel
controls
follows . M ore d etaile d infor m ation is given und er
General

GAIN

Screw d
river ad j ustment p ermits
O p erating I n formation .

A dju stment

cali b ration
of d eflection factor .
VO L TS/DI V
Selects calibrate d vertical d eflection
factor from 5 m V / d iv to 5 V / d iv in
α 1, 2, 5 se quence
.
VA RIA BLE

P rovides uncalibrate d varia b
le
d
e
( VO L TS/DI V )

flection factors . E xten
d
s
t he
h ig h est d eflection factor to at least
12 .5 V / d iv . P us h k nob in an d
re-
lease to activate ; the k nob moves
outwar d from t he VO L TS/DI V
control w h en activate d .
VA R B A L

Screw d river a dju
stment p ermits
A d j ustment

b alancing
of the am p lifier for
minimum
trace s h ift w h ile rotating
t he VA R IA BLE
control .
I
N
PU T

BN C connecto r for applying exter-
Connector

ηαΙ signals .
General
FIRST-TIME O PER ATIO N
7 Α 15
Wh
en s h ippe d from t he factory, t he 7 Α 15
h as been cali-
P OSITIO N
Controls vertical p ositio n of oscillo-

br ate d
to meet the s p ecifications listed in
Section 1 and is
sco pe d is p lay .

rea d y
to be u se dwith an in d icator oscilloscope .

Operating Instructions-7A15
T h e following ste p s d emonstrate the basic op eration of
t he co n trols of t he 7
Α 15 . It is recommen d e d t h at t h is pr o-
cedure be
followe d
com
p letely for familiarization with t he
instrument . O p eration of t he oscilloscope an d time-base
unit is d esc r i bed in t he instr u ction ma nu al for t h ese units .
Setu p I n formation
1 . I n sert t he 7 Α 15 i n to α vertical p
lug-in com p artment
of α 7000-series oscilloscope .
2 .
Insert α 713--series time- b ase unit i n to α h o r izo n tal
p lug-in
com partment .
2-2
3 .
Set t
he
controls as follows :

Fig .
2-1 . Oscilloscope dis p lay w h e nch ec k ing amplifier Gain .
7 Α
15 ( L eft V ert com p artment)
P
OSITIO N

Midrange
POLARITY +UP
VO
L
TS/DI V 10 m V
CO
UPL
I N G DC
VA R IA BLE
CA L IN
713511 ( Β H oriz com p
artment)
L evel/Slo p e

Ce n tere d on p ositive slo
p e
Triggeri ng
Mo de

Ρ - Ρ A u to
Coup ling

AC
Source

I n t
Time/Div

1 ms
Variable (Time/Div)

Cal In
M agnifier

Χ 1
ΒDelay
Mode

I ndepen d ent
P osition

Mid range
7504 (Indicator
Oscillosco p e)
V ertical Mo de

L eft
Horizontal Mode

Β
Β
Intensity

CCW
Calibrator

1
kH
z,
40 mV
Β Trigger So u rce

L eft Vert
4
. Connect t he oscilloscope to
αp ower sou r ce w h ic h
meets
t he voltage an d frequency re q
uiremen ts of t h e oscil-
loscope power su pp ly .
7 . Co nn ect
t
he
Cali
b
rator ou t pu t to t h e 7 Α 15 INPU T
conn ector .
8 . C h ec k t he C R T d is p lay for fo u r d ivisions of vertical
deflection (see Fig . 2-1) . If necessary, ad j ust t he fro n t
p anel
GAI N for fo u r d ivisio n s of vertical d eflection .
9 . P ress the ID E NTI F Y b
utton an dch ec k t h at the d is-
play moves
u p ward about 0 .3 divisions . Also ch ec k
t
h
at the
rea dout information
on the
C RT is replace d by the wo r d
"ID EN TI F Y" .
10 . P ress and release the VA R IA BLE control to its out-
ward p ositio n . Turn t h e VA R IA BLE control fully cou nter-
cloc k wise, and ch ec k for 1 .6 d ivisions or less d is p lay am p li-
tude . P ress t he VA R IA BLE control to the CA L IN p osition .
11 . C hange t he VO L TS/DI V to 0 .1 V, Calibrator Volts
to 0 .4 V an d t h e Triggeri n g Sou rce to Ext . Connect the
Calibrator
out p ut t h ro ugh α" Τ " connector to the time b ase
Ext Trig
In an d t he 7 Α 15 I NPU T con nector . Set the
P O L A R ITY
switc h to I NVER T to d is p lay t h e opp osite
polarity of t he
s q
uare
wave .
T h is com p letes t he basic op erating p rocedure for t he
7 Α 15 . I
nstrument operations not ex p lai ned h ere or op era-
tions w h
ic
hneed
furt h er exp lanation are d iscusse d und er
General
O p erating I n formatio n .
5 .
Turn
t he oscillosco pe p ower
on
and allow about 5

CO NTR O L S E T
UP C
H
A R T
minutes warmu p .
Figure 2-2 s h ows t h e front panel of t h e
7
Α 15 . T h is c
h
art
can be re p ro ducedan d use d as α front p a n el record for
6 . A d vance the Β Intensity until α free-r u nning trace is

sp ecial
meas u rements, a pp
lications
or p
roce
du res, or it may
observe d . A d j ust the P ositio n controls to center
t
he t r ace

b
e
used
as α training ai d for familiarization with t h is instru-
οη t he C RT .

ment
.

7 Α 15 T E ST S E T-
UP C H A R T
σ » οί ~ ορρν
POSITION
V A R B A L
INPUT
imp
20 pF
ΤΕΚΤ R ΟΝΙ
%®
7
Α 75
P OLA R ITY
Π
+
UP
-/I NVER
T
V A R IA BLE (CA L IN)
V O L TS/DI V
Ί- Ί AC
GN D
υ DC
AMPL IF I ER
F ig . 2-2 . 7 Α
15 control set u pch
art .
O p erating
Instructions-7A15
2- 3

O pe r ati ng Instructions-7A15
G ENER A
L
O
PER ATI NG I NF O RM ATIO N

T h e GND p osition is also use d to p re-c h arge t h e coup ling
ca p acitor to t he average level of t h e signal app lie d to t h e
Signal
Con n ection

I NPU T connector . T he p re-c h arge network allows t h e i npu t
In general,
prob es offer the most convenient means of

coupling ca p acitor to c h arge to t h e DC source voltage level
con necting α signal to t
he in pu t of t he 7 Α 15 . Tek tronix

whe n t h e CO UPL I N G switc h is set to GN D .
p ro b es are s h iel ded to p
r event p ic k up of elect r ostatic inter-
fere n ce . Α 10
Χ atten u ator p robe offers α h ig h inp u t im-

T he
p edance an d allows t h e circuit un d er test to op erate very

procedure for using th is feature is as follows :
close to normal operati ng con d itions . H owever, α 10 Χ
p robe also attenuates t h e inp u t signal ten times .

1 .
Before connecting the signal con taining α DC com-
p onent to t he 7 Α 15 INPU T, set the CO UPL I NG switc h to
GND . T h en connect t h e signal to the I NPU T connector .
In h ig h -fre qu ency a pp lications re q uiring maximum over-
all b andwid t h , use α coaxial ca b le terminate d at both end s
in t h e ch aracteristic imp e dance of the ca b le . To maintain
t h
e
h ig h
-fre q
uency c h
aracteristics of
t he
a pp
lie d signal, use
h ig h - q
uality low-loss cable .
R
esistive coaxial attenuators
can be u se d to min imize reflections if t h e a pp lie d signal h as
s
u ita b le
am
p
litu
de .
In p ut Cou p ling
T h
e AC-G N D-DC lever switc h allows α c h oice of in p ut
co
u p ling . T he ty pe
of
d
is p lay d esire d d etermines t h e mo d e
of in pu t co u pling u se d . T h
e
DC p
osition can be use d for
most a pp lications . However,
if t he DC com ponent of t h e
sig n al is muc h larger t han t he
AC com p one n t, t h e AC
p osition will p robably p rovi d eα better d is p
lay . DC coupling
s h ould be use d to d isplay AC signals b
elow about 2 h ertz
an dsqu a r e waves containing low-frequency
com ponen ts, as
t hey will b e attenuate d in t he AC p osition .
Ι
η the AC p osition, t he DC com p onent is bloc kedby α
ca p acitor in t h e in p ut circ u it . T h e low-frequency res p onse
in t he AC position
is
abou
t 2 h ertz (-3
dB
point) .
Th ere-
fore, some
low-frequency
attenuation
can
be exp ecte d near
t h is fre q uency limit . Distortion will also app ear in s q uare
waves w h ic h h ave low-fre q uency com p onents .
2- 4
2 .
Allow
a bo u t
two
seconds for the coup ling ca p acitor
to ch arge .
3 . R eset t h e CO UPL I N G switc h to AC . T he trace
( d isplay) will remain on t h e scree n and t he AC com p on ent
of t he signal can b e meas u re d in th e normal manner .
H ig h -level low-frequency
signals
can b
e
con n ecte d direc-
tly
to the
7
Α 15 I NPU T conn ector with sh ort unsh ielded

Deflection F actor
leads using α BN C to Banana J ack A da p ter . T h is met ho d
wor k
s best for signals below about one k ilo h ertz an d d eflec-

T he amou nt of vertical d eflection p ro du ce d by α signal is
tion factors above one volt/ d ivisio n .
Wh en t h is met hod is

d etermine d by t he sig n al am p litu d e, t h e atten u ation factor
u se d , esta b lis hα common ground
between t he 7 Α 15 and of t he p ro b e (if any), t he setting of t he
VO
L TS/DI V switc h
t he
e q
uipment
un d er test
(common
groundp rovi d e dby

and t he setting of the VA R IA BLE control (if co n trol is i n
line cord s is usually
ina
deq
uate) . Attem p t to p osition t h e

t he outwar d p ositio n ) . T h e calib r ate d d eflection factors
in-
lea d s away from any source of interfere
n ce to avoi d errors

dicated b y t h e VO L TS/DI V switc happ ly
only w h en t he
in t he d is p lay . If interfere n ce is excessive
with uns h ielded

VA R IA BLE control is in t he inward (CA
L IN) p osition .
leads, use α coaxial cable or α p ro b e .
T he VA R IA BLE control p rovides uncali b
rated vertical
d eflection b etween t he calibrate d
settings of t he VO L TS/
DI V switc h , an dexten d s the maximu m d
eflection factor to
at
least 12 .5 volts/ d ivision .
T h e GAI N
control, α fro n t- p anel screwd river ad j ustment,
sets
t he gai n of the 7 Α 15 in t he 10 m V / d iv p osition of t he
VO
L TS/DI V switc h . T he gain calibration of t he unit s hou
l d
be ch
ec k ed for acc u racy p rior to ma k i n g critical measure-
ments, using eit h er t he oscillosco p e cali b rator ou t p ut or α
sta nd ar d am p lit ude calibrator . If a d j ustment is necessary,
t he GAI
N
s h oul
d b e a d ju ste d with t he VO L TS/DI V switc h
set to 10 m
V .
V
ariable B
alance
To c
h ec kan d /o r a dju st the VA R B A L, p roceed as fol-
lows :
1 . Set the CO UPL I N G to GND an d a d just the time- b ase
T he GND position p rovi d es α ground reference at t he

controls for α free-running trace .
am p lifier in p ut . T h e signal a pp lied to t h e I NPU T connector
is p resente d wit hα one mego h m load, w h ile the am p lifier
in
pu t is grounded . T h is eliminates the nee d to externally

2 . P ress and release t h e
VA R IA BLE control to its o u t-
gro und the I NPU T to esta b lis hα DC gro u n d reference .

war d p osition .