Tektronix 7A16A User manual

1 Ν ST F t U C - Γ 10 Ν
ΜΑΝ
V A L
7
Α 16 Α
A MP L
I F I ER
Serial Nu mber
Te k t r o n ix,
Inc .
t Ρ .
Ο . Box500

t

B eaverton, Oregon 97005

+

Ph o ne : 644-0161 t Ca b les : Te k tronix
070-1378-00

772

W A RR AN TY
All TEK TR O N IX instr u ments are warrante d against
d efective m aterials an d wor k ma ns h i p for one year . Any
questions with res p ect to th e warranty s hould be ta k en up
with you r TEK T R O N IX F iel d Enginee r or re p r esentative .
All requests fo r r e p ai r s an d r e p lace m ent p arts s h ould be
d i r ecte d to the T EK TR O N IX F iel d Office o r r ep r ese n tative
in yo u r ar ea
.
T h is will assure you t he fastest p ossible
service
. P
lease incl u d e t he instrument Ty pe Nu mbe r or P art
N
umbe
r
and Serial Nu m be r with all re q uests fo r p arts or
service .
S p ecificatio n s an
d
p r ice
c
hange p rivileges
reserve d
.
Copy r ig h t © 1972 by Te k tronix,
Inc ., B
eaverton,
O
r
egon
.
Pr i n te d in t h e U nited States of
America . All, rig h ts reserved .
Conte n ts of t h is pu b lication
may
not
be
re pro
d uced
in
any
fo r m with out permission of Te k tr onix, Inc .
U .S .A . an d foreign T EK T R ON IX pro d ucts cove r ed by U .S .
and foreign patents
and/or
paten
ts p
e nd ing .
T EK T R O N IX is α registere d t r ademar kof Te k tro n ix, In

TA BLE O F CO N T EN
TS
S E
CTIO N 1

S PE CI F ICATIO N
S E CTIO N 2

O PER ATI NG I N ST RU CTIO NS
SECTION3

CIRCUIT DESCRIPTION
SECTION
4

M AINTENANCE
SECTION 5

CALIBRATION
SECTION
6

ELECTRICAL PARTS L IST
Abbreviations an d Symbols
P
arts Ordering Information
SECTION 7

DIAGRAMS AND CIRCUIT B OARD
ILLUSTRATIONS
Symbols and R eference Designators
SECTION 8

MECHANICAL
PARTS LIST
M echanical Parts L ist
Information
Index of M echanical Parts
Illustrations
M echanical Parts L ist
Page
Intro d u ction

1-1
Electrical C h aracteristics

1-1
En vi r
onmental C h ar acteristics

1-2
Ph
ysical
C h aracteristics

1-2
Installation

2-1
Function of Controls
and Connectors

2-1
B asic O p eration

2-2
General Operating Information

2-2
Ap p lications

2-3
B lock Diagram Description

3-1
Detaile d Circuit Description

3-1
Preventive M aintenance

41
Troubleshooting

4-1
Corrective
M aintenance

4-3
Performance
Check

ς -1
Test Eq
ui
p
ment R e q uired

ς -1
Short
Form
Proce
d
ure

ς -2
Calibration Procedure

5-3
B alance

5-4
Gain

5-4
Com p
ensation

5-5
B andwi
d th
and
Risetime

5-6

Fig .
1-1
.
7
Α 16 Α
Amplifier Plug-in
.

Introduction
T h e 7 Α 16 Α Am p lifier Plug-in U nit is α wi d e-ban d wi d t h
am
p lifier
d
esigne d for use with T EK TR O N IX 7000-Series
C
h
aracte
r ist i cs
Deflectio n F acto r
Cali brate d Range
Acc ur acy
Un cali br ate d (V AR IA BLE)
Gain R ange
F re quency R es p o n se
Ba ndwi d t h
AC Co up le d ( L owe r B andwi d t
h
L
imit)
1
10 Hz or less .
20 MHz Bandwi d t h
Ste
pR es po n se
20 MH z B a n d wi d t h R iseti m e
M aximu m
In p
ut
Voltage
DC Co
u pled
AC Co
up le d
S PE CI F ICATIO N
TA BLE 1-1
ELE CTR ICA L
Pe r fo r ma nce R equ i re m e n ts
5 m V / d iv

to

5 V / d
iv,

10 ste
p
s

i n

α

1-2-5
se qu ence .
W it h i n 2 ο
/
ο of in d icate d d eflectio n facto r wit h
GAI N a dju ste d at 10
m
V / d iv .
Co n tin u ously varia b
le betwee n calibrate d ste p s ;
exten d s d
eflectio n facto r to at least 12 .5 V/ d iv .
Wit h 7400-Se r ies

Ι

Wit h 7500-Series
60 MHz

Ι

90 MHz
W it
h 7700-Series

W
it h 7900-Se r ies
150 ΜΗτ

225 MH z
R
iseti
m e

Ι

W it h 7400-Series

W it h 7500-Series
5 .9 n s

3 .9 n s
W it h 7700-Se
r
ies

W it
h
7900-Series
2 .4 n s

1 .6 ns
Section 1-7 Α 16 Α
Oscillosco p es . T h e 7 Α 16 Α can be o perated in any p l u g-in
com p artme n t of 7000-Series Oscillosco p es . Rea d out
enco d ing an d trace i d entify f u nctions are p rovide d to
r eadout e q ui pp ed oscillosco p es .
S up p lemen tal Information
P e rm its a dju st m e n t of d eflectio n facto r for
cali br ate d o p er ation wit h
all
7000-Se r ies main-
fra m es .
20 MH z, ±3 MHz .
21 n s maxi mum .
250 V (DC
+
pea k AC) ; Α com
pon ent
500
V
Ρ - Ρ maxim
um, 1
kH
z
or
less .
500 V (DC
+ peak
AC) ;
Αcom p one n t 500 V
Ρ - Ρ
maxim um, 1 kH z or less .

S p ecification-7A16A
TA BLE 1-1
(
εοπ t)
C
h a r acte r istics

Pe r fo rm a nce
R
eq
u i r eme n
ts

Su p p lemental
Informatio n
Input
R
and
C
R
esistance

1 ΜΩ t2% .
Capacita nce

20 p F ±0 .5 pF .
Ove rd rive R ecove r y Ti m e
DC Drift
TA BLE 1-2

TA
BLE 1-3
ENV
I
R O
NMEN TA
L
CH A R ACT ER ISTICS

PH YSICA L
0 .1 m s o r less to recover to
wit h i n one d ivisio n
after re m oval
of ove rdr ive sig n al of up to
+75
d iv or -75 d
iv rega rd less of ove rd rive sig n al
du ration .
D r ift wit hTi m e (Ambient Tem p
0 .02 d iv o
r
less in any one
min u te afte r one
an d L ine V oltage Co n sta
n t)

h
our
warm up .
D
r ift
wit
h
Te
mp e r
at
ur e
(
Line

Ι

N ot m ore than 0 .02 d iv/ ° C .
V oltage Co n stant)
Size

F
its all
7000-Se r ies p l u g-i n co m pa r tments .
R efer to t h e sp ecificatio n s fo rt he associate d
oscillosco pe .

W eig ht

0 .9
kg or 1 .9 l bs .

O PER ATI N G I N
ST RU CTIO N S
General

POSITION
Installation
inscribe d wit h t he unit i d
entification "7 Α 16 Α ") and t h e
plug-in
will un latc h . Continue p ulli ng on
t he latc h to sli de

GAIN Ad j ustme n t
t h e
7 Α 16 Α o u t of t he oscilloscope .
F unctions of
Controls an d Co n nectors
F ront Panel
I NPU T Co n nector
P
rovi d es signal connection
to t he am p lifier .
AC-G N D-DC Switch
Selects sig n al i npu t
coup ling mo de .
AC : T he AC com po n e n t of t h e signal
is cou p led to t he
in p ut w h ile t h e DC com ponent is b loc ke d .
DC :
B
ot h AC and DC com p onents of t he sig n
al is
coup
le
d to t he amplifier i np ut .
P O L A R ITY Switc h
P rovi d es α mea n s of i n verting t h e
d
is p
lay .
B
A N
D W IDT H Switc h
Sectio n 2-7
Α 16 Α
To

effectively

use

t he

7 Α 16 Α ,

t he

operation

an d
Controls p osition of t he trace .
capabilities of t
h
e instrume n t must be k nown . T h is section
d escribes
front-panel co
n
trol
f u
nctions, general information
on sig n al in p ut
co
nn ections,
an d ot h er sub j ects t h at p ertain

ID EN TI F Y P
us
hbu
tton
to various measurement
app
licatio
n s .

Deflects trace about
0 .3 d
ivisio
n for trace i d entification .
In i n str u ments with rea
d out,
also re
p laces rea d o u t wit h t h e
wor d "ID EN TI F Y" .
T h e 7 Α 16 Α is cali br ate d and rea
dy for use as receive d . It

VO L TS/D I V Switch
can be
installed in
any com partment of T EK TR O N IX
7000-Series Oscillosco
p es, but is inten d e d for u se p rimarily

Selects cali b rate d d eflection factors from
5 mV / d iv to
in vertical p lug-i n com partmen
ts . To install, alig n t h e u pp er

5 V / d iv ; 10 ste p s in α 1-2-5 se qu ence .
and lower rails of the 7 Α
16
Α
with t he oscillosco p e trac k s
and i n sert t he p l u g-in . T h e front
panel will b e fl u s h wit h t he
fro n t of t h e oscillosco pe w h e n t he p lug-in
is inserted, an d

V A R IA BLE
(
VO L TS/DI V )
t he latc h at t he b ottom-left corner will
be in place against
t he front
p anel .

P
rovi d es continuously variable uncali b rated
settings be-
t w
een
calibrate d ste p s . E xte nd s t h e deflection
factor to
To remove t he 7 Α
16
Α ,
pull on t he latc h(wh
ic h is
12 .5 volts/ d ivisio n or m ore .
Screw
d
river
ad ju stment permits calibratio n of d eflection
factor
.
+ UP : Α positive-goi ng signal at
t h e I NPU T con n ecto r
d eflects t h e C R T d isplay up
ward .
I NVER T : Α positive-goi ng sig n al
at t he
I
NPU T con-
nector d eflects t he C RT d is p
lay
d ownwar
d .
Pr ovides α m ea n s of limiti n g t he upper ban d wi d t h .
FULL : Allows t h e 7 Α 16 Α to op erate at f u ll rate d
GND : Gro u nds t he am p lifier in p
ut w h ile main taining t he

b an d widt h .
same loa d at t h e I NPU T connector . P rovi
d es α p at h for
p re-c h arging t h e AC cou p ling ca p acito r
(t
h
is feature p ro
tects
b ot h

t he 7 Α 16 Α an d t h e so u rce
generator from

20 MH z : R e d uces t he u pp er b andwi d t h of t h e 7 Α 16 Α
to
p ossi b le
over-voltage conditions)
.

about 20 MH z .

O peration-7 Α 16 Α
B ASIC O PER ATIO N

T he T EK TR O N IX Ρ 6053 p ro b e is eq ui pp e d with α
rea d out cod ing ring w h ic h connects to α circ u it
in
t
he
Ge n eral . T h is proce d ure d emonstrates t h e use of t he

am p lifie r unit . T h is automatically corrects t
h e rea
dout
co nn ectors a nd controls of t h e 7 Α 16 Α , w h ile at t h e same

d is p layed on t h e C
R T
to t h e actual d
eflection factor
at
t he
time provi
d
ing
α
mea n
s of
check
ing th e basic operation of

ti
p
of t he p ro b e .
T h
is p ro b
e is recommen de d for use wit h
t he instrument .

t he7 Α 16 Α and an oscilloscope
e q u i p pe
d
wit h readout . T he
T EK
T
R O N IX
Ρ
6054 p ro b e is
electrically ide n tical to t he
Ρ
6053 b ut is
inten
d
e
d for use wit
h systems not eq u i pped
Pr eliminary Set up . I n
stall t
he 7 Α
16
Α
into any 7000-

wit h rea d out . For more information refer to t he Te k tronix,
series
oscilloscope vertical compartment an d set t
he
oscillo-

Inc . catalog .
sco p
e VER TICA L M
OD
E
an d
T R IGG ER SO
UR C
E
to t he
p
ro
p er setti
n gs
.
Install α 7-series time-base unit into α h o r izontal

Vertical Gain C h ec k and A d j ustment
com partment an d set t he oscillosco p e HO R IZO N TA L
To ch ec k t he gai n of t he 7 Α 16 Α , set t he VO L TS/DI V
M OD E to t h e p ro p er setting . Set t he time- b ase unit to α

s w
itc h to 10 mV a nd connect α40 m V, 1 kH
z
sig n al from
swee p rate of on e-milliseco ndper division an d set t he

the
oscillosco
p
e calibrator
to t
h e In p
ut
connector . T h e
triggeri ng mode to
A
U TO .

vertical
d
eflection
sh ould be
exactly four
d
ivisions
.
If
not,
a d ju st t he front panel
GAI N for
exactly four divisions .
Proced u re
1 . Set t h e 7 Α 16 Α AC-G N D-DC switc h to GND and
p ositio n t h e trace to t h e ce n ter of t he graticule .
2 . Set t he VO L TS/DI V switc h
to 10
m
V an d apply α
40 m V 1 kH z s q uare-wave signal from t h e oscilloscope
CA L I BR ATO R to t he 7 Α 16 Α I NPU T connector . Set t he
AC-G
N D-DC
switc h to DC and ch ec k for α fou r - d ivisio n
dis p lay .
3 . Set P O L A R ITY switc h to I NVER T
an d
ch ec
k t h at
t h e dis p laye d signal is inverted as compared
to its ap p ear-
ance in step 2 .
4 . Set t he AC-G N D-DC switc h to AC a nd ch ec k t h at
t h e trace is centere d on t h e C R T g r aticule .
5 . Set t h e oscillosco pe CA L I BR ATO R to 4 m V and t h e
7 Α 16 Α MAG switc h set to ιΧ 10 . C h ec k for α fo u r- d ivision
d is p lay .
6 . P ress t h e 7 Α 16 Α ID EN TI F Y bu tton, c h ec k t h at t h e
d is p lay moves u p ward a pp roximately 0 .3 division an d t h e
rea dou t (if so e qu ip p e d ) rea d s "ID EN TI F Y" .
G EN E R A L O PER ATI NG I NF O RM ATIO N
Signal Connectio n s
In p ut Co u pling
T
he AC-G N D-DC switc h allows α ch oice of in p ut
cou p ling met h od s .
T
h e ty p e of d is p lay d esired a nd t he
app
lie
d
signal will determine
t
h e cou p li ng
to use .
T he DC cou pling p osition ca n be use d for most
ap p lications . For AC signals wit h f r e q uencies b elow a b out
30 H
z
(10 H z wit hα10 Χ p robe), an d s q uare waves w h ose
low-frequency com p onents are imp ortant to t he display, it
is necessary to use DC cou pling to obtain α satisfactory
p resentation .
In t he AC coup li n g p ositio n t he DC component
of
t h e
signal is b loc ked b yα ca p acitor in t he in pu t circ u it . T he AC
coup ling position p rovides t he best display of signals wit h α
DC
com p onent muc h larger t h an t he AC com p on ent . T h e
p re-c h
arge feature s h oul d be use d w hen t h ere is α p ossi b ility
of h aving
α
resi
d
ual c h arge
on t
h e
i np ut ca p acitor of t h e
op p
osite polarity
to t
he
inte nded i
np
ut, and w h en t h e
algebraic sum of t h e com b i n atio n of ch arges
may b
e
greater
t han t h e maximum in p ut limitations
of
t he
am
p lifier .
To
use t h is feature, first set t he coupling switc h
to
GN D,
th
en
connect t he pro b e to t h e circ u it an d wait about two
seco
nd s for t he coup ling ca p acitor to c h arge, set t h e
coup ling
switc h to AC .
In general, p robes offer t he most co n venie n t mea n s of

T h e G N D p osition p rovi d es α ground reference at t he
con necting α sig n al to t he i n p ut of t he 7 Α 16 Α . Α 10 Χ

inpu t of t h e am p lifier without externally grou nding t he
atten u ator pro b e offers α h ig h im p e d ance and allows t h e

In p u t connectors . However, t h e signals connecte d to t he
circ u it under test to p erform very close to normal o p erating

in pu
ts are not gro
und
ed, and the
same DC
loa d is p resente d
con
d itions .

to t he signal source .

V O L TS/DI V
and V A R IA BL E

2 . Set t he
Co
u pling
switchto AC .
T h e amount of d eflectio n produced
by α sig n al is
d etermine
d by t he signal amplitu d e, t he attenuatio
nfacto r
of t heprob e, t h e setting of t he
VO
L
TS/DI V switch , and
t he setting of t h e VA R IA BLE
Control
.
Calibrate d
d eflection factors re p resente d b y t h e
setting of t he V O L TS/
DI
V switch apply only w hen t h e V A R IA BLE
con trol is i n
t he CA L p ositio n ( p ush e d -in) .
T
he VA R IA BLE control p rovides
variable
u
ncalibrate d
settings between t h
e
cali brated ste p
s of t he VO L TS/DI V
switch . W it h t h e V A R IA BLE control
outset
fully
cou nter-
clockwise
the uncalibrated d eflectio nfactor is
exten d ed to
at least 2 .5 times t he atte n uator setting .
By a pp
lyi
ng α
calibrate d voltage source to t h e I NPU T conn ector, any
specific
d eflection factor can be set with in t he range of
t
h e
V A R IA BLE
con trol
.
P olarity Switch
The P O
L
A RITY
switch p rovi d es α means of inverting
t h e
d is p laye d signal . W it h t h e P OL A R ITY set to + UP, α
p ositive-going sig n
al at t h e
I
NPU T p ro d uces an up
ward
d eflectio nof t he CRT
display .
W
it h t h e P O L A R ITY set to
I NVER T, α p ositive-going signal
will p ro d uce α d ownwar d
d eflectio nof t h e CR T d isplay .
Trace I d entification
Wh en t he ID EN TI F Y b utton is p
resse d , t he trace is
deflecte d u p war d about 0 .3 d ivision
to
i
dentify t
h
e 7
Α
16 Α
trace . T h is feature is p articularly usef u l w
h
en
multi p le
traces are d isplayed on the CR T . In
mainframes wit h
rea d out, it also re p laces t h e d eflection factor rea d out wit h
t he wor
d
"ID EN TI F
Y" .
General
A PPL ICATIONS
P ea k
-to-
P
ea
k
V oltage M easurements (AC)
Toma
k
e
pea k -to- peak voltage meas u rements, use
t
he
following p
r oce d ure :
1 . Apply t
h e
signal to t he In p ut connector .
ΝΟΤΕ
ΝΟΤΕ
P osition to
ce n ter vertical
line
Operation-7A 16A
For
low-frequency signals below about 30 h ertz, use
the DC position to prevent
attenuation of the signal .
3 . Set t h e VO L TS/DI V switchto d is p lay
about
five
vertical d ivisions of t h e waveform .
4 . Set t he time-base Triggering
controls for α stable
d is p lay . Set t he Time B ase to α swee p
rate w
h
ic h dis p lays
several cycles of t h e waveform .
5 . Tur n t he 7 Α 16 Α P OSITIO N control so the lower
p ortio n
of t
h
e waveform coinci d es wit h o ne of t he gratic u le
li n es
below t he center h orizontal li n e, and t he topof t h e
waveform is wit h in t he viewi ng area . W it h t h e time
base
P
osition co n t r ol, move t h e dis p lay so one of t he u pp er
p
ea
ks lies
n ear the center vertical line (see F ig . 2-1) .
6 . M easure t he d ivisions of vertical d eflection p eakto
p
ea
k . C heck
t h at t h e V A RIA BLE control is i n t h e CA L
p
osition .
This
technique can also be used to make measu r e-
ments between
two
p
oints on the waveform, r athe r
t han p ea k to peak .
T he following i n
formation d escribes the p r oce d ures a nd
tech ni q ues for
ma
k ing
meas
u
rements with α 7 Α 16 Α an d t h e
associate d
T EK T R
O N IX oscillosco p e and time-base . T h ese
a pp licatio n s are n ot d escri bed in d etail, since eac h a pp lica-
tio n
must b
ead
a pted to the re q ui r ements of the i nd ivi d ual
m eas u rements
.
T h
is instrument can also b e used for many
app lications
w
h ic h
are n ot described in t h is manual .

defle
V e r c
ti
ι co ι
n
Co n
tact your local T EK T R O N IX F iel d Office or represen
t-
ative
for assistance in ma k ing s p ecific measureme n
ts wit h
t h is
instrument .
F ig . 2-1 . M eas ur i ng t h e p ea k -to-pea k voltage of α waveform .
2-3

Ope r ation-7 Α 16 Α
7 . Mu lti p ly t h e d istance measu re d in ste p7b y t he

5 . Set t h e time- b ase Triggeri n g controls fo r α sta b le
V OL TS/DI V switc h setting . I n clude t he attenuation factor

d is p
lay .
Set t he Time Base swee p rate for an o p ti m um
of t he p robe if used .

d is p lay of t he waveform .
EXA MPLE : Assu me t h at t h e peak
to p
ea k vertical

6 . Measure t h e d ista n ce in d ivisio n s between t h e refer-
d eflectio
n
is
4
.5 d ivisions
using
α 10
Χ
attenuator p robe,

ence line and t he p oint on t he waveform at w h ic h t he DC
and t
he VO L TS/DI V switc h is set to 1 V .

level

is to

be measured .

For exam p le, in

Fig . 2-2 t he
measurement is between t
h e reference line
an d p oint
Α .
vertical
VO L TS/DI V
p
ro b e
Volts = d eflection Χ

Χ atten u ator
( d ivisio n s)
setti n g
facto r
S ub stituti n g t he given val u es :
Volts P
ea
k to P ea k = 4 .5 Χ 1 Χ 10
T he p ea k -to- p ea k voltage is 45 volts .
If you are usi ng α 7 Α 16 Α wit h α cod e d pro b e an d an
oscillosco p e equ i pp e d with
rea
do
u
t, si
mp ly m u lti p ly the
d
istance measured in ste p 7 b y
t
he deflection factor
d is p laye don t he CRT
.
Instantantous V oltage Measurements (DC)
To measure t he DC level at α give n point on α waveform,
p rocee d as follows :
1 . Co n nect t he signal to t h e In p ut connector .
2 . Set t he VO L TS/DI V switc h to d isplay about five
d ivisio n s .
3 . Set t h e Co up ling switc h to G ND an d p osition t he
trace to t he bottom graticule line or ot h e r r efe r ence line . If
t he voltage is negative wit h res p ect to grou nd , p osition t he
trace to t he to p gratic
u le li ne .
Do
n
ot move t he
POSITIO N
control after t h is
reference
line h as b
een
establis h e d .
NO ΤΕ
7 . E sta b lis h t he p olarity of t he waveform . W it h t h e
+ UP /I NV switc h i n t h e
+
UP p ositio n , a ny p oi n t above t h e
reference line is p ositive .
8 . Multiply t h e d ista n ce measured i n step 7 by t h e
VO L TS/DI V switc h setti n g . I n clude t h e atte n uation facto r
of t h e p robe, if use d .
EXA MPLE : Assu me t h e vertical d ista n ce measure d is
3 .6 d ivisions (see Fig . 2-2) and t h e waveform is above t he
r eference line usi ng α 10 Χ p r obe with α VO L TS/DI V switc h
setting of 0 .5 V .
U sing t h e form u la :
Instan- vertical

VO L TS/ p ro b e
taneous = d istance

Χ polarity Χ

DI V

Χ atte n uatio n
V oltage ( d ivisions)

setting facto r
S ub stit u ti n g t he given values :
Instantaneo u s Voltage
=3
.6 Χ 1 Χ 0 .5 VΧ 10
T he instantaneo u s voltage is 18 volts .
To measure α voltage level with r espect to anot h e r
Ve
r
tical
voltage rat her t h an groun d, ma k e t h e following

distance
c h anges to Step
4 .
Set t h e Coupling switc h to DC and
apply t h e refe r ence voltage to t h e Input con n ecto r .
T h en position t h e trace to t h e r efe r ence line and
disconnect t h e r efere n ce voltage .
R efe r e n
ce line
4 . Set t h e Cou p ling switc h to DC . T he gro und refe r ence

'

'
line can b e ch ec ke d at any time by switc h ing to t he GND

F i g , 2 .2,
Meas
u ri ng i n sta n ta n eo u s voltage wit h respect to same
position .

reference .

Comparison
M
eas
u
rements

Th
is is the vertical conve r sion factor .
In some a pp licatio
n
s it may b e d esira b le to esta b lis
h
u nits of
m
easurement oth er th an t hose indicate d b y t he
VOL
TS/DI
V switch
. T h
is is partic
u larly
useful w h en
com p aring un k nown
signals
to αreference amplitu d e . One
use fo r t h e compariso n -measureme n t tec hn i q ue is to facili-
tate calibratio
nof e qu i p ment
w
h ere
t
hed esire
da
mp litu
d
e
does not pro d
u ce
an
exact number
of d
ivisions
of d
eflec-
tio n . T he a d j ustment will be easier and mo r
e
accurate if
ar b itrary units of measurement are esta b lis
h
e d , so t h at t
h
e
correct ad ju stme
n t is i
nd
icate d byan exact numb er
of
d
ivisions
of d
eflection . T he following p roced u re d escri b es
h
ow to establis
h
ar
b
itrary
u nits
of
meas u re for com p
arison
measurements .
To esta b lis h α ve rtical d eflection factor b ase d upon α
s p ecific reference amplitu d e, proceed as follows :
2 . Set t
h
e VO
L TS/DI
V switchand t h e V
A R IA BLE
con trol to prod
uce
α d is p lay w
h
ic
h
is an exact
number
of
ve rtical d ivisio n s in am p litu d e . Do
not ch
a nge t h e
VA R IA BLE con trol after ob tai n ing t he desire d d eflection .
V ertical
Conversion
F
actor
Ope r
ation-7A16A
_

reference
signal
am
p
litu d e (volts)
vertical d
eflection Χ

V
O
L TS/DI V
( d
ivisions)

setti n g
5 . To measure t he am p litude of an un k nown signal,
d isco nnect t h e refe r ence sig n al a nd conn ect t h e unknown
signal to t h e
I np
ut connector
. Set
t
h e VO L TS/DI V switch
to α setting t
h
at p
rovides s u fficient vertical deflection
to
ma kean accurate
meas u rement .
Do
not re-a
d ju
st t h e
V A R IA BLE
control
.
6 . M eas u re t h e vertical deflection in d ivisions and
calculate t he am p litu d e of t he u nk nown signal using t h e
following formula :
Signal _ VO L TS/DI V
vertical

vertical
1 . Co n nect t
hereference signal
to t
he
In pu t co
nnector
.

Am
p
lit u d e

setting

Χ
conversio n Χ d eflectio n
Set t h e time-base
sweep
rate to d isplay several
cycles of
t
h e

factor

(divisio n
s)
sig n al .
E XA MPLE : Assume αreference signal amplit u d e of 30
volts, α VO L TS/DI V setting of 5 V a nd t he VA
R IA BLE
control ad j usted to pr ovi de α vertical d eflection of
four
d ivisions .
S ub stit
u
ting t
hese values in t he vertical co n version factor
formula (step
4) :
3 .
To
esta b lis han arbit r ary ve r tical d eflectio n factor so
t he am p litu d e of an u n k nown signal can b e m easure d

V ertical Conversion

-_

30 V

=

1
.5
accurately at any setti ng of t h e V O L TS/DI V switch , t h e

F actor

4 Χ 5 V
am p lit u de of t h e reference signal must be kn own . If it is
not kn own, it ca n b e
m
eas u re dbefore t he VA R IA BLE
control is set in ste p 2 .

T h en withα VO L TS/DI V setting of 2 V, t h e p ea k to p ea k
am
p lit ude
of an unknown
sig n
al
w h ic hp r od uces α vertical
d eflection of five d ivisions can b ed etermi ne d by using t he
4 . Divide t he am p lit u d e of t h e reference signal (volts)

signal am p litu d e fo r mula (ste p 6) :
b a rt h e product of t h e vertical d eflection ( d ivisions)
establis he d in step 2 and t he setting of t h e V O L
TS/DI
V Signal
switc h .

Am p litu d e

2
V

Χ

1 .5

Χ

5

=

15
volts

Introduction

T
h
e outp ut of t h e Signal Splitter Am p lifier is co
nnected
to t he oscilloscope mai n frame via t he interface
connector .
T h is section of t h e manual contains α
d escri p tion of t he
circuitry u se d in t h e 7 Α 16
Α
am
p lifier . T h e 7A1 6A d escri p -
tion begins withαd
iscussion of t h e instr u me n t usi ng t h e
b loc k diagram
s h ow nin t he Diagrams section . T h
e
n
, each
circuit is d
escribed in d etail using b loc k d iagrams
to s h ow
t he
interconnections b etween stages in
eac h
ma j
or circuit
a nd t h e relations h ip of t he front- p
anel controls to t h e
in d ivi d ual stages .
Com p lete sc h ematics of
eac h circ u it a r e give n in the
Diagrams section
. R efer to th ese sc h ematics t h roug h out t
he
following
circ u it d esc r iptio n for electrical
val u es
and
relations
h ip .
BL OC
K DIAG R A M
Th e signal to b e d is p laye d
on t h e C RT is ap p lie d to t h e
I NPU T connector .
T h e sig n al p asses t hrou g h t he in put
cou p ling switch
, w here
t
he approp riate cou p ling is selecte d ,
to t he attenuators .
T he VO L TS/DI V switch selects t he
correct amount of
atten u ation and t he signal is p asse d to
t he
In pu
t
Source F ollower .
T he P olarity Amplifier provides α
conve n ient mea n s of
inverting t he d is p laye d
trace . T he out put of t he
P
olarity
Amplifier d
rives t h e 2 Χ Gain Am p lifier :
CI R C U
IT D E SC R I P TIO
N
R eadout enco d ing circuitry
u
se d
i n
t
h e 7 Α 16 Α is
standard to t h e 7000-Series .
D E
TAI LE D CI RC U IT D E SCR I P TION
AC-G N D-DC Switch
In put signals
connecte d to t h e I NPU T connector can b e
AC-co u ple d ,
DC-couple d , or i n ternally d isconnecte d .
S100A is α
cam-ty pe switch ; α contact-clos u re ch a r t
s h owing t h e operation is given on t h e sc he
m
atic d iagrams .
Wh en t h
e
AC-G
N D-DC switch is i n t he DC p ositio
n , t he
I NPU T signal is connecte d d irectly to t h e atten
u ators .
In
t he AC p osition, t he I NPU
T
signal
p
asses t
hro u gh ca p acito r
C10 . T h e cap acitor prevents
t he DC component of t he
signal from passing
to the am p lifier . T h e GN D
p
ositio
n
o p ens t he
signal path and con n ects t h e inpu t circ
u
it of
t he
amplifier to ground
. T h is p rovi d es αgroundreference
wit h out t h e need to discon n ect t he a p plie d
signal from t he
I NPU T connector .
R
esistor
R 102, co nn ected across t he
AC-G N D-DC switc
h , allows C10 to b e p re-c h arged in t h e
G ND p ositio n .
In p ut Attenuator
Section
3-7 Α 16 Α
W it h t h e VO L TS/DI V switch set to
t he 5 mV an d

Th e effective
overall d eflection facto r of t h e 7
Α
16
Α
is
10 m V p ositio n s, t h e
signal connecte d to t h e

I N PU T

d ete r mi n e d by t
he setting of t he VO L TS/DI V switch
,
connector is p asse d
t h roug h t h e attenuators υη -attende d .

S100
B . T h e b asic deflection
factor is 5 millivolts p er
To ac h ieve α
deflection factor of 5 mV /Div t h e gain of t h e

d ivision of
CRT d eflection . To increase t h e b asic d eflection
2Χ Gain Am p
lifier is increase d from one to two . Inter n al

factor to t
h e val u es i nd icate d on t he front panel,
p
recisio
n
gain an d b ala
nce a
d ju
stments are incl u ded in t he am p lifier .

attenuators
are switched into t he circuit . S100
B
is α
ca
m -type switch and t h e dots on t h e contact-closure c h art
(see Diagram 1) in
d icate w hen t h e associate d contacts are in
Overall GAI N and VA R IA BLE gain is a dj uste d in t he

t h e positio n s h
own
(o penor
close d ) . In t h e 5 m V /Div and
Gain

Amplifier . V aria b le B alance and h ig h f r equen cy

10 mV /Div p
ositions, t h e atten u ators are n ot used ; t
he
a dj ustme n ts a re also controlled in t he Gain Am
p
lifier
.
T he

in pu t
sig n
al is
co nnected d irectly to t h e Sou r ce
F ollower .
out p ut of t he Gain Amplifier is connecte d to t
he P
osi-

T he 10 mV /Div
positio n decreases t he gain of
t he 2 Χ Gain
tioni ng circ u itry w h ere t h e
P
OSITIO
N
an dID
EN TI F Y

Amplifier . F or switch positions above
ten millivolts p er
fu nctions are controlle d .

d ivision, t he atten u ators are switc he d into t
h
e
circ u it singly
o r i n pairs to p ro d uce t h e d eflection factor
in
d
icate d
on
t h e
front panel . T h ese h ybrid atte
nuators are fre qu ency
T he Signal Splitter Am p lifier provi d es d ifferential sig n al

com p en sate d voltage d
ividers . F or DC and low-frequency
ou t p uts fo r t he signal line and t
h
e trigger
line . T h is stage

sig nals, theattenuators
are p ri m arily r esista nce d ivi d
ers
an
d
contains α b andwi d t h limiter t
h
at
limits
t
he upp er fre qu e n -

at
h ig h f r e quencies t he atten uator b ecomes p
rimarily
α
cy res p onse to 20 MH z .

cap acitive divi d er .

Circ u it Desc r i p tio
n
-7 Α 16
Α
In a dd ition to provi d ing constant attenuatio n at all

Position Circuit
freq u encies wit
h in
t
h e
b a nd
width
of
t he i n strume n t, t h e
inp
u
t
attenuators are designe d to maintain t he sa m e in pu t

Positioning current is added to
t h e sig n al curre n t of
RC c h aracteristics (one mego h m Χ 20 pF ) . Each attenuator

U 550 output from t
he c u rrent sources Q720 and Q730 .
8736
co n tains
an
a dj ustable series ca p acito r to p rovi d e correct

controls t he voltage at t h e b ases of t he curre n t
attenuation at
h ig h fre q uencies,
and an
a dj usta b le s h u n t

so
u rces w h ic h i n tur n d etermi n es t h e amo u nt of positioning
atten
to provide
correct in pu t ca p acitance .

current a dd
e
d .
Wh e n t he ID EN TI F Y switc h is close d t h e
capacitor current
t
h roug h Q730 is red u ce d causing t h e CR T trace to
deflect .
In p ut Source F ollower
Q1 50A and Q140 form α casco de am p lifier wit h Q1 50B
p rovi d ing α constant cu rrent .
R
132 limits t he cu rrent drive
to t
he
gate of Q150A
. Dual-dio
d
e C R
130 p
rovides circuit
protection b y limiting t he voltage swing at t he gate of
Q150A to a bou t ±9 volts . R 134, C130,
and t he capac-
itance of R 130 p rovi d e low freq uency com p ensation
.I
np ut
capacitance for t h e 5
m
V an d10 mV p ositions is set b y
C134 .
T
he outpu t to t
h e P
olarity Amplifier
(
U 350)
is from
t h e source of Q150A and
h ig h fre q uencies from t he
collecto r
of
Q140 . R 164 is use d to b ala n ce t h e in p ut to t he
P ola r ity Am p lifier .
Q820, Q840, Q860, an
d Q880 are use d as level s h ifters
to return t h e DC
level of t h e d is p lay signal to zero .
Polarity Am p lifier

Am p lifier Q820-Q840
are switc h ed on w hen t he BA N D-
W IDT H switc h is
in t he full p ositio n . W it h t h e B
A N D-
U 350 is α p ara ph ase
type amplifier with
α d
u
al
differen-

W IDT H switc h in t h e 20 MH z p ositio n Q860-Q880
is
tial outp ut ca p a b ility . P olarity of the outp ut is selecte dby

switc he d on . Α filter in t he collectors of
Q860- Q880 limit
gating
t
he co ntr ol b ases of eit h er t h e i n verte
dout
p ut or t he

t h e b a nd wi d t h . C R 860 an d CR 880
isolate t h e filter from
υη -inverte
d

o
u t pu t . Τ 301

is
α

b alun transfor m er
a
n d

t h e outp ut w h en in th e
FULL m od e .
p rovi d
es differential drive
to U350 at
h ig h fre qu encies .
C334 a nd R 334 t h ermally com pen sate for gm c han ges i n
Q1 50A .

T h e t r igger signal ci r cuitry is similar to t
he d is p lay signal
circ u itry wit h Q920 an d Q940 as level
s h ifters fo r t he
FULL b an dwidth position and Q960 and
Q980 as level
2 Χ Gain Am p lifier

sh ifters for t h e 20 MH
z
b a nd wid t
h p osition .
T h e o u t pu t of t h e P olarity Amplifier is casco ded to
U 450, integrate d circ u it U450 is t he same ty pe as U 350 . In

Connectors
t h e 5 m V position, full d rive is p rovi d e d to t h e followi ng

All t
h e conn ectio n s ma de to t h e main frame b y t h e
stage from pins 6 an d 8 of U 450 . In t he 10 mV positio n
pins 5and 9
provi d e dr ive to t he followi n g stage . R 436

7
Α
16
Α are
s
h own
on
t h e connecto r s p ortion of
Diagram 1 .
pi
Also s h own are
t h e power su pp ly d ecoupling com p
onents .
p
rovides low
fre q uency t h ermal compensatio n . DC b alance
between t he 5 m V and 10 m V positions is ad j uste dby
R 453
.
CR 507 an d R 507 maintains α constant input voltage

Readout Encoding
w h ile switc h i n g b etwee n t he 5 m V an d 10 mV p ositio n s .
Gain Am p lifier
Integrate d circuit U 550 is t he same type as U 350 . Both
d iffere n tial outputs of U 550 are p a r allele d to p rovide d rive
to t he next stage . In t he CA L IN positio n R 516 sets t he
gain for t h e entire a mp lifier by a dj usti n g t h e c u rrent at t he
control bases of U 550 . In t h e υη -cal position t he
VA R IA BLE control, R 515, increases t he gain of t h e entire
am p lifier up to 2 .5 times .
R
531-
R
537 compensate for
tem p erature va r iations . C531 an d
R
531
are h ig h f r e q uency
ad j ustments . DC b alance over t h e VA R IA BLE range is
a
dju ste d b yR 553
.
'4'

P ,1 1
3-2
Signal Sp litter Am p lifie r
I n tegrate d circuit U 750 is t he same ty p e as
U
350 .
T he
two differential outp uts of U 750 are connecte d to
se p erate
common base tra n sistor am p lifiers to p
rovi
d
e seperate
d is p lay and trigger signals .
Both out p uts of U 750 are biase d
e q ually to p r oduce
e q ual sig n al outp uts . R 770, C770, and
L 770 are h ig h fre q
uency com p ensation
a
d j ust m e n ts for t he
dis p lay signal . L 770 is selecte d at t
h e factory and nee d not
b e c h ange d u nless U 750,
Q860, o r 0880 is re p laced .
T he R ea dout Enco d ing circuit consists of switc h ing
resistors an d p ro b e se n si ng stage Q620 . T h is circuit encod es
t h e R ow and Column outp ut li n es for rea dout of d eflectio n
factor, uncalibrate d deflection factor
(V A R IA BLE) i n for-
mation, an d signal
inversion .
Data
is enco d ed on t h ese
outp ut
lines
by switc
h ing resistors between t h e m a nd t he
time-slot in p ut lines
or
by
current a dd ed t h ro u g h Q620 .
R 647-C647 are switc he d between time-slot t h ree (TS-3)
and t h e Col u mn outpu t line w h e n t he CA L switc h is i n t h e
υη -cal position . T h is res u lts in t h e sym b ol > (greate rt h a
n)
b ei n g dis p laye d prece d ing t h e d eflection factor reado
u
t .
R 648 is switc h ed between TS-2 an d t h e Column outp ut line

Ci r c u it Descri p tion-7 Α
16
Α
w h e n t h e POLARITY switc h is in th e I NVER T p osition .

resistor R 622 . Wh en t h e -15 volt time-slot p ulse is a p p lie d
Th is res u lts in t he sym b ol

j

(inverted) b eing dis p layed

to Interface Co n nector
Β
33, Q620 is interrogate d an d its
prece d ing t he d eflection factor rea d o u t .

collector current is
ad de d to the
col umn
current ou t pu t
t h
ro
ug h Interface Connector Α 37 .
Switc h ing resistors are u se d to in d icate t he setting of t h e
VO L TS/DI V switc h to t he mainframe rea dou t system . T h e
dots on t h e con tact-clos u re c h art (see Diagram Sectio n )

W it h α 1 Χ probe (or no p robe) connecte d to t he I NPU T
in d icate w h en t h e associate d contacts on t he VO L TS/DI V
co nn ecto r , 0620 is turne d off . T h e d eflection facto r
cam switc
h
are
close
d .
R 633, R 634,
and
R
635
select
t
h e

rea d out is determined b y the VO L TS/DI V switc h p osition .
number
1, 2, or 5 d
e p en
d
ing on
t
he com
b
i n ation
t
h
at
is

W it hα10 Χ p robe connecte d , t he bias on Q620 allows 100
switc hed
in . R 637 selects t h e m (milli-) prefix an d R 639

microamperes of collector cu rrent to flow . T h is increases
selects
t
h e symbol V (volts) in t h e 5 mV t h roug h .5 V

t he deflectio n factor readout by α factor of 10 .
(500 m V )

positions of t h e

VO L TS/DI V switc h .

R 638
selects t he sym b ol V
in
t
h e 1, 2,
an d 5
V
positions .
R
630,
R 631, and t heou t pu t of t
h e p ro
b
e sensing stage
(Q620)

T h e ID EN TI F Y
b
utton (S45 on Diagra m
1) d
oes two
select t h
e
d
ecimal p oint (n umb er
of
zeroes), agai nd e-

t h ings w hen p resse d :
p en
d
ing
on t
h e resistor combination switc h e d in by t he
VO L TS/DI V switc h .

1 . It causes t he trace re p resenting t h e 7 Α 16 Α to move
(see t he discussio n on t he P osition Circuit) .
P ro b e sensi n g stage Q620 i d en tifies t he attenuatio n
factor of t he probe con n ecte d to t he I NPU T co nn ector b y

2 . Forwar d b iases CR 621 and Q620 to result in α
sensing t he amount of cu rrent flowing t h roug h t h e p robe

sufficie n t amount of collector current w h ic h r ep laces t he
cod i n g resisto r locate d in t h e p robe connector . T h e output

d eflection factor rea dout with t h e wor d "ID EN TI F Y" .
of t h is circuit corrects t he mainframe rea d out system to
i n cl ude t he p ro b
e
atte
n uation facto r
.
T
he t h ir d
contact
of
t he
I NPU T
connector
p rovi
d
es
t
h e i np
ut to t
h e p
robe

T h ese two actions ai d in i d entifyi n g t h e 7 Α 16 Α trace
sensing d
evice from t h e p
ro
b e cod ing resistance
(co
d ed w h en multi p le traces are d is p laye d . Wh en t h e ID EN TI F Y
probes
only ; see O p erating Instructions)
.
T he t h ir d contact

b utton is release d , t he deflectio n factor rea d out is restore d .
i s also use d for t h e ID EN TI F Y input . T h e co d ing resistor
forms α voltage divi d er wit h R 621 t hrough CR 621 to t h e
-15 V s upp ly . T he resultant voltage sets t h e b ias on Q620

For f u rt h er infor
m
ation on t
he
op eration of t he reado u t
an d d etermines t he collector c u rrent, alo ng wit h emitter

system, see t h e oscillosco pe
instr u ction man u
al
.

M AI N T EN A N C E
Introduction

L
ubrication
T h is sectio n of t he manual co n tai n s mai n te n ance i n for-

U se
αcleaning-type lubricant on s h aft bu s h ings, inter-
mation for use in preventive mai n te nan ce, corrective

connecting plug contacts,
a nd switc h contacts . Lub ricate
mainte
n
an
ce,
an d troublesh ooting of the 7
Α
16
Α .

switch d etents withαh eavier
grease .
Α
lu b rication k it
containi n g t he n ecessary l ub ricating
mate r ials and
i n structions is availa b le t h ro ugh any T EK TR
ON IX
F
iel d
F urt h er m ainte n a nce

i n formatio n relati ng to ge n eral

Office . Or d er TEKTRONIX P art N umber
003-0342-00 .
mainte n a nce can b e foun d in the i n st r uction manuals for
t he 7000-series oscillosco p es .
PREVEN TI VE M AI NTEN A N C EGeneral
T R O UBL ES H OOTI NG
Section 4-7A16A
T he following is provided
to
augme n
t i
n
formation
General

containe d in other sections
of
t h is man u
al w h en tro ub le-
s h ooti ng the 7 Α 16 Α . T h e sc h ematic
d iagrams, circuit
P reventive maintena n ce, co n sisti ng of cleaning, visual

d escri p tion, and calibration sections s hould be use
d to full
inspection, etc ., p erforme d on α regular basis, will im p rove

ad vantage . T he circ u it d escription section gives
d
etaile
d
t
he r eliability of t h is i n str u ment . P erio
d
ic ch ec k s
of
t he

information on circuit beh avior a nd out put requ ireme n
ts
.
semico n ductor d evices use d i n t h e un it are n ot recom-
mended
as α
preve n tive mai n te n ance measure . See
semicon
ductor-check
ing information given under Tro ub le-

Trou b les h ooting Aids
s h ooti ng .
Cleaning
Diagrams
. Circuit d iagrams are give n on fol d ou t p ages in
Section 7 . T he circuit number
an d electrical val u e of eac h
component in t h
is inst
r ume n
t
are s
h ow n on t he diagrams .
Im p orta nt voltages ar e also sh
ow
n .
Circuit
B
oar
d s .
T he
ci r cuit b oard s use d in t h e 7 Α 16 Α are
Avoid t h e use of chemical cleaning age n ts w h ic h

outline
d
on
t he
sc
h
ematic
diagrams, a ndph otograph s of t he
might d amage t h e plastics use d
in
t h is
instrument .

b oar d s are s h
ow
n
on
t heback
s of t
he
sc h ematic d iagrams .
Special care s h ould b e ta ken wh en cleaning t he

E ac h b oard -mou n te d electrical
component is i d entifie d on
P oly ph enyle n e Oxide attenuato r boa r d . Do not apply

t h e ph otograph by its circuit number .
any solve n t
containing
k
etones, esters or h alogenated
h yd r oca r bons . To clean, u se only water sol ub le
d eter gents, eth yl, meth yl or
isopropyl alco hol
.

Com p onent and W iring Color Co d e . Colored
stripes or
d ots on resistors an d ca p acitors signify electrical
values,
tolerances, etc ., accor d ing to t h e ΕΙΑ sta n d ar d color
code
.
F ront P anel . L oose d ust may b e remove d wit hα soft

Com p onents not color coded usually h ave t he value p rinte
d
clot h or α d ry br us h . W ate r a nd mil d detergent may be

on t he body .
use d ; h oweve r, a b rasive clea n er s s h o u l d not be u sed .
T
h e insulate d wires u se d for interco nn ectio n i n t h e
Inte r ior . Cleaning t h e interior
of t he unit sh oul d prece de

7
Α
16 Α are color coded to facilitate tracing wires from one
calibration,
since
the
cleaning

p
r ocess could alte rt he

p oi n t to an oth er i n t h e unit .
settings of t h e cali b ration a dj ustments . U
se low-velocity
compresse
d
air
to b
low off
t
h e accu m u
lated d
u
st . H ardene d
dirt can be
remove
d wit
h
α soft, dry br
us
h , cotton-tippe d Semicon d uctor L ead Configuration . T h e lea d config u -
swab, or clot
hd
am
p ene
d with α
mil
d detergent a nd water

ratio n s of t he semicon d uctor d evices used in t h is instru-
solutio n .

ment are s
h
own on the sch ematic d iagrams .

M aintenance-7 Α 16 Α
Troubleshooting Equipment

4 . C h ec k I n str u ment Perfor m an ce . C h ec k t he cali br a-
tion of t he unit or t he affecte d circ u it, by p erformi n g
T he following eq ui p ment is useful for
troubles
h
ooting

P
erformance C h ec k of
Section
5 .
T h
e app arent tro
u
ble may
t
he 7 Α
16
Α .

only
be
α
res u lt of mis-a dj ustment, and may b e correcte d
b y calibration .
Co
mp lete cali b ratio n instr u ctions
are
give n
in Section
5 .
1 .
Semiconductor Tester-Some means
of testing t h e
tra n sistors, d io d es, and FE T's use d in t h is i n st r ume n t is
hel p ful . Α t r ansistor-curve trace r suc h as t h e T EK T R ON IX

5 . C h ec k V oltages . Often t h e d efective compone n t or
Ty p e 576 will give t he most com p lete informatio n .

stage can b e locate d by
c
h ec k ing for t he co rr ect voltage in
t h e circuit . Typical voltages are give n on t h e d iag r ams ;
howeve r , t h ese are not ab sol u te
a nd
m
ay vary slig h
tly
2 . DC Voltmeter and O hm meter- Α voltmeter is re-

b etwee n instruments
. To
o b tain
op
erating con
d itions
qu ire d for chec k ing voltages wit h in t he circ u its, an d an

similar to t h ose use d to ta ke t h ese rea d ings, see
t
h
e
o h mmeter for ch ec k ing resistors an d d io d es .

instructions in t h e Diagram section .
3 .
Test Oscillosco p
e- Α test
oscillosco p e is re qu ired to

6 . C
h
ec
k In
d ivi d ual

Components .

T h e

following
view waveforms
at
different
points
in
th e
ci
r
cuit
.
Α

met hod
s are provi de d for c h ec k ing t h e in d ivi d u al com-
T EK T R ON IX 7000-series Oscilloscope e q uippe dwith α

p on e n ts . Com pone n
ts w
h ic
h are sol d ere d in place are b est
readout system, 7D13 Digital Multimeter unit,
713-series

ch
ec ked by disconnecting one en d to isolate t he meas u re
Time- B ase unit, andα 7A-series Amplifie r unit with α 10 Χ

ment from
t
he
effects of su rr oun d ing circuit r y .
pro b e will meet t he n ee d s of b ot h items 2 an d 3 .
NOTE
4 . P l u g-in Exte
nd
er- Α fixt u re
t
h
at p ermits o p eration of
t
he unit
ou tside of
t he p l u g-in com p
artment for b
etter

To
locate intermittent
or tempe
r
ature sensitive com-
accessibility du ring tro ub les h ooting . Order T EK T R O N
IX

ponents mo u nted on t h e atten u ato r b
oa rd, Q u ί k
P art Number 067-0589-00 .

F reeze (Miller Step h enson, M S-240, T EK T R
O N IX
P
art Num b er 006-0173-01) is r ecommen ded . Dry
ice
or d ί
c h lord ί -fluo r remet h ane ( Fr eon 12, Dup ont o r
Can- Ο -Gas)
may also
b
euse
d . Ot her types of circuit
Troubleshooting Procedure

coolant may d amage t he poly
ph enylene oxi d eboa r ds .
Th is tro ub les h ooti ng proce d ure is arra n ge d in an or de r
w h ic hch ec k s t he sim p le trou b le p ossi b ilities b efore p ro-

Α .
TR A N SISTO R S . T h e best c h ec k of tra n sistor
ope
r
a-
cee d ing with extensive tro ub les h ooting .

tio
n
is act u al p erformance und er op e r ati ng cond itio n s . If
α
tra
n
sistor is s u specte d of being d efective, it
can best be
c h ec k edby
substituting α compo n e n t kn ow n to b e goo d ;
1 . C h ec k Co n t r ol Setti n gs . An i n correct setti ng of t h e

however,
be s
ur
e t
h
at circuit cond itions are not s u c h t h at α
7 Α 16 Α controls can in d icate α trouble t h at does not exist .

re p
lacement migh t also
bed amage d . If s ub stitute transisto rs
If t h e r e is any q uestion about t h e correct function or

are not availa b le, use α
dynamic tester (suc h as
o p eratio n of α con trol or fr on t-pa n el con n ecto r , see t h e

T EK T R ONIX Type 576) .
Static-ty pe testers may b e u se d ,
O p erating I n str u ctions sectio n .

b u t si n ce t hey do not ch ec k
operation und e r si m ulate d
op erati n g con d itions, some d efects
may go u nnoticed . Be
sure t he powe r is off b efo r e attem p ting
to remove or re p lace
2 .
C h ec
k
Associated

Eq
ui
p ment
. Before procee d ing

any
transistor .
wit h trou b les h ooti ng of t
h
e 7
Α
16
Α
ch ec k t h at t he
e q ui p me n
t
use
d
wit h t h is i n st r ume n t is
ope
r ati ng co r rectly .
If p ossible, s u bstit u te an am p lifie r u n it kn ow n to be

Β . DIOD E S . Α d iode can be c h ec k e
d
for
an open o r
op erating correctly i n to t h e indicator un it an d see if t he

s h o r te d cond itio n b y meas u ri ng t he resistance between
problem p ersists . C h ec k t h at t he i nput sig n als a r e p r o p erly

terminals
. Wit h
an
o h m
m
eter scale h aving an internal sou r ce
conn ecte d a nd t h at t he interco nn ecti ng ca b les are not

of b etween 800 millivolts
and 3 volts, t h e resistance s h oul d
d
efective .

be ve r y h ig h in
one
direction
and very low w hen t h e lea d s
a r e reversed .
3 . V is u al Ch ec k . Vis u ally ch ec k t he p ortion of
t
he
instrument in w h ic h t he trouble is sus p ecte d .
Many
trou b les
ca n b e locate d b y visual indications, suc h as unsol d ere d
conn ectio n s,

b ro ken wi r es,

d amaged

circ u it

b oar d s,

Do not use αη oh mmete r scale t h at h as αhigh
internal
da m age d com p onents, etc .

c urr ent
. High c u rrents may damage t h e diodes .
4 2

C . RE SISTO RS . C heck resistors withan oh
m m eter .
R esistor tolerance is
given in th e E lectrical P
arts
L ist .
R esistors n ormally d o not
need
to be
re p lace
d
u nless t h e
meas ur
e
dvalue
varies
wi d
ely from
the specifie d
value
.
4 . T EK T R O N IX P art N umber .
7 .
R
e p air
and
R ead j ust t he Circuit . Special
tec
h ni ques
re q uire d to re p lace com p onents in t h is unit are given un d er
Com p one n t R eplacement . B e sure to check t h e pe r form-

Soldering Techniques
ance of any circuit t h at h as b een r epaire d o rt h at h as h a d
any electrical com p o n ents re p lace d . R ecali br atio nof t he

W A RN I N G
affecte d circ u it may b e necessary .
General
CO
RRE CTI V E M AI NT EN AN C E
Corrective maintenance consists
of
com p onent replace-
me n t and i n st r ument repair . Special tech ni ques re quired to
replace com ponen ts i n t h is i n strume n t are given h ere .
Obtaining R e p lacement P arts
Stan d ar d P arts . All electrical and m ech anical part re-
p lacements for t h e 7 Α 16 Α can be obtaine d t h roug h yo u r
local T EK T R O N IX F iel d Office or representative . H oweve r ,
many of t he electro nic components can be ob tai n e d locally
in less time t h an is re qu ire d to or d er t h em from Te k tro n ix,
Inc . B efore pu rc h asing or ord ering replacement p arts, ch ec k
t h e parts list for value, tolerance, rating and descri p tion .
ΝΟΤΕ
Wh en
selecting
r eplacement parts, it is
important to
remem b er t hat t he physical size a nd s h a p e of α
component may affect t h e perfo r mance of t he
inst
r ument,
particularly at high frequencies . All
re-
p laceme n t p ar ts s h ouldbe d irect r e p lacements unless
it is k nown t h at αdifferent com p onent will not
adversely affect instrument p e r for mance,
M aintenance-7 Α 16 Α
Or
d
er
all s p
ecial p
arts d
irectly from your
local
T EK T R O N IX F iel d Office o r re p resentative .
Ordering P arts . Wh en ord ering re p lacement parts from
Te k tronix, Inc ., inclu d e t he following information :
D .
CA
P ACITO RS . Α lea kyor s horted capacitor
can
b e
d
etecte
db
y check ing r esista nce withan o h mmeter on t h e

1 . Instrument Ty pe .
h ig h
est
scale . U se an oh mmeter w h ic h will n ot excee d t h e
voltage

rating
of t
h e
cap
acitor . T h e resista nce rea d i n g

2 . I n strume n t Serial N umber .
sh ould be
h ig h after initial ch arge of t he cap acitor . An open
capacitor can best be d etecte d wit hαcap acitance meter, or

3 . Α description of t h e p art (if electrical, incl u de circuit
by check i n g w h et h er t h e ca p acito r passes AC signals .

n umber) .
Disconnect t h e instrument from t h e power sou r ce
b efore sol d er ing .
Atte nuator Circuit B oar d . T h e Attenuator Circuit B oar d
is ma d e from p olyp henylene oxi d e because of its excellent
electrical ch aracteristics . U se mo re t han n ormal care w
h en
cleaning or solderi n g t h is
m
aterial . T h
e
followi
n g
rules
s h oul d be observed w hen re
m oving
or replaci
ngp
arts
:
1 . U se α low-wattage sol d
ering
iron (not over 15
watts) .
2 . Do not app
ly more h eat,
or apply
h eat for
α
lo n ger
time, t h an is a b solutely necessary .
3 . U se some
form
of
vac uu m sol d er re m ove r w h e n
removing m u lti-lead devices .
4 .
Do not apply any
solve n
t co
n
tai
n ing
k eto
n es, esters
or h alogenate dhydrocarb
ons .
5 . To clean, use only water-sol ub le detergents, eth yl,
met h yl or isoprop yl alcoh ol .
Ci r cuit B oar d s (exce p t Attenuator b oa
r
d) .
T
he co
m -
Sp
ecial

P
arts .

In add itio
nto
t
he
stan d ar d
elect r
o
n ic

p
onents mo unted on t h e circuit boar d s in t he am p lifier can
com p onents, some s p ecial p arts are used i n t he 7 Α 16 Α .

be re p lace d using normal circuit boa rd sol d er i ng tec
h
ni
ques
.
T h ese parts are man u facture d or selecte dby Te k tro n ix, Inc .

K eep t h e following points in
m i nd w h e n soldering
on
the
in accor d ance withour s p ecifications . T h ese special p arts

circuit boar d s :
are in d icate d in t hep arts list by an asteris k p rece d ing t he
p art n um b er . M ost of t he mec h anical parts used in t h is

1 . U se αpencil-type sol d eri ng iro n wit hα(wattage)
instrument h ave b een manufacture d by Te k tronix, Inc .

rati n g from 15 to 50 watts .
4 3

M ai n tenance-
7 Α 16 Α
2 . Apply
heat from t he sol d eri ng iron to t h e junction

R eplacemen t semicond uctors s
h oul
dbe of t
he original
between t he
component
an
d t h e circuit b oa r d .

type or α direct re p laceme
n
t .
T he
sc
h ematic
diagram
s h ows
t
h
e lea dco
n figurations of t he semicond uctors use d in t h is
instr
u
ment .
If
t
h e replaceme n t semico n ducto r is not of t h e
3 . Heat-s h u n t t
he lea
d
to t he com ponent by means of α

original
ty p
e, c h ec k t h e man u fact u rer's b asi n g d iagram for
p air of long-nose
pliers
.

p
ro p er b asi n g .
4 . Avoid excessive heating of t h e ju nction wit h t h e

Circuit B oar d R emoval
circuit b oard, as t h is coul d se p arate t h e circuit boar d wiring

In general, t h e circ u it boards used in t
he
7
Α
16
Α n ee
d
from t he b ase material .

never b e remove d unless t h ey must be re p lace d .
E lectrical
connections to t he b oar d s are ma d e by sol d ere d con
5 . U
se electronic gra d e 60-40 tin lea d sol d er .

nections .

If

it

is necessary to re
p
lace α circuit b
oar
d
assembly, use t h e following p roce d
ures
.
6 . Cli p off any excess lea d lengt h exten d
ing beyon d t he
circuit boar d . Clea n
off
any
r esi d ual flux with α flux-
removing solvent .
M etal Terminals . Wh en sol d ering metal terminals (po-
tentiometers,
etc .) use 60-40 ti n -lea d sol d er an dα15 to 50
watt sol
d ering iron . O b serve t h e followi ng precautions
w h e n sol d ering metal terminals :
1 . Apply only enoug h h eat to ma ke t he sol d
er
flow
freely .
2 . Apply only enough sol d er to form α soli d con-
nection . E xcess solder may im p air t h e function of t
he p
art
.
3 . If α
wire
exten d s
beyon
d
t he sol d er j oint, cli p off t h e
excess .
4 . Clean t he fl ux from t h e sol d er j oint with α
flux-
removing solvent .
Com p onent
R
ep
lacement
WARNING
Α . RE ADOUT CI R C U IT BOA R D REM OVA L
1 . Disco n nect t
he wires connecte d to t h e outside of t h e
b oard .
2 .
R
emove t
he seven screws h ol d ing t h e boar dto t h e
mo
u nting
s
u rface .
3 .
Disconnect t h e wires connected to t he i n si d e of the
boar d .
4 . R emove t he boar d
from
t
h e unit
.
5 .
To
re p lace t he b oar d , reverse t he or d er of removal
.
Β . ATT E N U ATO R CI R CU IT B OA R D REM OVA L
1 .
R
emove t
he readou t b oar d as outline d in t he
p revious proce d
ure .
2 . Disconnect t h e in d uctor, ca p acitor, an d two groun d
stra p s connecte d to t h e rear of t he b oar d .
3 . . Loosen t h e front set screw on t
he VA R IA BLE
control s h aft cou p
ling (use
α
0 .050-inc h h ex- k ey wrenc h
) .
Disconnect the equipment from the power source
before
replacing components .

4 . R emove t h e re d VA R IA BLE con trol k nob and glass
rod from t h e con trol s h aft .
Semicon d u ctor R e p laceme n t . Transistors s h oul d not be
re p lace d unless actually defective . If removed from t h eir

5 . R emove t he
remaining front-
p
anel
k
nobs usi n g α
soc k ets d uring routine maintenance, ret u rn t h em to t h eir

1/16-inch h ex- key wrenc
h .
original soc k ets . Unn ecessary re p lacement of transistors
may
effect t h e cali br ation of t h is instrument . Wh en
transistors are re p laced, ch ec k t he pe r fo r mance of t
h e p art

6 .
R emove t h e fro n t p anel from t he instrument by
of t h e instrument w h ic
h
may
b e affecte d .

p ryi ng at center
bottom wit h screwdriver .

8 . Disconnect t he wires and resistor from t he I NPU T
BN C con nector .
10 . R emove t he attenuator boar d wit h cam switc h from
t he instrument .
C . A MPL I F I ER
CI R C U
IT B OA RD
REM O VA L
1 . R emove
t
hep lastic
plug-in
gui
d
e
from t he rear of the
instrument
.
2 . Disconnect
t
he wires connected
to t
he
boar d
from
the front- p anel controls .
3 . L oose n t h e h ex-socket screw in t h e cou p ling of t h e
V A R IA BLE control s h aft using α 0.050-inc h h ex- key
wrenc h . Pull t h e VA R IA BLE k nob an d glass s h aft from t h e
front of t he instrume n t .
4 . Disconnect t he in d uctor, capacitor, and two groun d
stra p s from t h e front of t he board .
5 . R e m ove t he screws and n uts securing t he boar d to
t h e c h assis or ot h er
mounting surface .
Switch R e p lacement

R ecalibration After R e p air
Several ty pes of switc h es are used in t h e
7
Α
16
Α . T
h e

After any electrical compo nen t h as b ee n r ep lace d , the
sli de and micro switch es s h oul d be re p lace
d as α unit if

cali b ration of t h at p articular ci r cuit s h oul d be c heck e d , as
d amage d . T h e following special mainte n an ce i n
formation is

well as t
he cali
b
ratio nof oth er closely relate d circuits .
p rovi ded for t he cam-type switch es .

R efer to Section
5
for t h ese p roce d ures .
7 . R emove t h e attenuator s h iel d s .
9 . R emove t h e I NPU T BN C co n nector .
11 . R ep lace by reversing t he R emoval Pr oce dures .
6 .
R emove t h e
boar d
from th e instr u ment .
7 .
To
replace, reverse t h e ord er of removal .
Α . CAM-TYPE S W ITC HE S
M aintenance-
7 Α 16 Α
Repair of cam-ty p e switches s h ould be unde r ta k en
only by
experienced
maintenance personnel . Switc h
alignme n t and
spring tension
of t h e contacts must be
carefu lly maintained fo r pro p er operation of t h e
switc h . F o r assistance in main tena n ce of cam-ty p e
switch es, contact you
r
local T EKTRO N IX Field
Office or representative
.
Α
cam-type switch consists of α rotating cam, w h ic h is
turned by t
he
front- p
anel
k nobs, an d α set of co n tacts
mou
n
te d on an
a
dj
acent circuit
b oard . T h ese switch
co
n
tacts are actuated by lo b es on t he cam .
T
h e VO LTS/
DI
V and AC-G
N D-DC
(cou pling) cam-ty p e switch es can be
disassembled for i n s p ection, clea n ing, re p air, or re p lace-
ment
as follows :
1 .
R
emove t h e
R
ea d out boar d an d t he Attenuator
b oard /switc h assem b ly as d escri bed p reviously . T h e front
switchsection on t
he
Atte
nuator board
is t
h
e
AC-G N D-DC
switchand t
he
rear
switc h sectio n is t he VO L TS/DI V
switch . T he switc h es are
now
open for inspection
or
cleaning .
2 .
To
com p letely remove th e switch from t heboard ,
remove t he two screws and fou r h exagonal posts w h ic h
h ol d t h e cam-ty pe switchto t h e circuit boar d .
3 .
To
remove t h e cam from the front s u pport block ,
remove t he retai n ing ring from t he s h aft on t he fro nt of the
switch a nd sli de t h e cam out of t h e su pp ort b loc k . B e
caref u l not to lose t h e small detent roller .
4 . To r e p lace d efective switc h co n tacts, follow t he
instr u ctions give n in the switch re p air k it .
5 . To re-install t he switch assembly, reverse t he above
p roce d ure .

Intro d uction

TE ST E QU I PM E N T RE
QU I RE D
To
assure i nstrument accuracy, ch ec k
t
he cali
b ration of

General
t h e 7 Α 16 Α every 1000 h ours of op eration
or
every six
mont h s if use d infreq u ently . Before complete calibration,

T he following test e q uipment an d accessories,
or its
t h oroug h ly clean an d inspect t h is instrument as outli ne d
in

e q uivalent,

is re q uire d fo r complete cali br ation of t h e
t h e Main te n a n ce section .

7 Α 16 Α . S p ecificatio n s give n for t he test e q u i p ment are t h e
minimum necessary for accurate calibration . T
h
erefore,
t h
e
s p ecifications of any test e q uipment use
d
mustmeet
or
excee d t h e liste dsp ecifications . All test equi p ment
is
T EK TR
O
N IX F
ield Service

assumed to b e correctly cali b rated and operating wit h in
t
h
e
liste d s p ecifications . Detaile d operating inst r uctions for t h e
Tek tronix,

Inc
.,
provi
d
es com p lete
instrume n t re p air

test e q ui p ment are not given in t h is p roce du r e . R efer to t h e
and recalibration service at local Fiel d Se r vice Cen ters a n d
instructio n ma n ual

for t h e test e q ui p ment if more
t h e Factory Service Center . Contact you r local fiel d office

info r mation is need e d .
or re p resentative for furt h er information .
P erformance C h ec k

S p ecial Calibration Fixtures
T h e performance of t h is i n st r ume n t can b e ch ec kedby
p erforming only t h e Ν/ C HE C
K
ste p s . P erformi n g t h e ste p s
mar ked wit hα V in d icate t h at t he instrument is ch ec ke d
against t he tole r a n ces liste d as α
Performan
ce R eq uireme n t
(see Sp ecification sectio n i n O
p
erators manual) .
L imits
and
tolerances given in
ot
h er c h ec k
ste
p
s are
cali b ratio n gui d es andsh oul d not b e i n ter p rete d as instru-
m ent s p ecificatio n s . O p erator fro n t- p anel a dju stments are
ad j uste d as p art of t h ePerformance C
h
ec k p roce du re .
CALIBRATION
Sectio n 5-7 Α 16 Α
Sp ecial TEKTRONIX
calibration
fixtures
are use d i n t h is
p roce du re only w h ere they facilitate
instrument cali b ratio n .
T h ese s p ecial calibration fixtu r es are availa b le fro m
Tek t r onix, Inc . Ord er by part n um b er t h roug h your
local
T EK TR O N IX Fiel d Office or re p r ese n tative .
Calibration Eq ui p ment Alternatives
All of t h e liste d test e qu i p ment is re q u ired to com p letely
ch ec kanda dj ust t h is instrument .
T
he Cali b ration
p rocedu r e is b ase d on t h e first item of eq ui p me n t give n as
Cali b ration

an exam p le of a pp lica b le eq ui p me n t . Wh en ot h er
equ i p ment is substit u te d , control settings or t h e calibration
To verify p ro p er cali b ration
of t h e 7
Α
16 Α a n d to

setu p may nee d to be altered slig h tly to meet t he
p revent unn ecessary re-calibration
of t
h e
entire i n stru m e n t,

re quiremen ts of t
h
e substitute
e q ui p
me
n
t .
If
t
h
e exact item
p erform t he A d ju st- p ortion of α step o n ly if t he tolerance

of

test

e q ui p m ent

given

as

an

example

in

t he

Test
given in t he C h ec k - part of t he ste p is n ot met
.

Eq ui p me n
t

list

is

n ot

availa
b
le,

first

c h ec
k

t he
Sp ecifications col u mn caref u lly
to
see if
any ot
h er
eq ui p me n t is available w h ic h migh t s u ffice . T hen ch ec k t he
For
best overall i nstrume n t perfor m an ce w hen per-

U sage column to see w h at t h is item of test eq ui p ment is
forming

αcomplete cali b ratio n proce
du
re,
ma k e eac h use d fo r . If use d fo r α ch ec k or a dj ustment w h ic h is of little
a d j ustme n t to the exact setti n g even if
t h
e
C h
ec
k - is with in

or no i mp orta n ce to your meas u reme n t req u irements, t h e
allowa b le tole r ance .

item and corres p onding step(s) can be d elete d .