Tektronix 178 User manual

ι
ι
178
577
D 1 /D2
S ERV
IC E

W A RN I N G
Teldfun m
@
THE
F
O LL O W I N G
S
ERV
ICI N G I N ST RU CTION
S
A
RE F O R US E BYQ U A L I F I
E D PER SO NNEL O NL Y .
T
O A V OID PER SO NA L I
NJUR Y, DO NOT
PERF
O RM ANY S ERV ICI
N G OT HER THAN
THAT
CO
N TAI
NE D IN O PER ATI
N G I N ST RU CTIONS
UNLESS YO U A RE Q
U
A L
I
F
I E D TO DOSO .
COMMITTED
TO E XCELLENCE
PLE AS E C HE C K F O R
C
H
A N G E I NF O RM ATIO N
AT THE RE AR O F T H IS M A
NU
A
L .
178
577 D1/D2
S ERV
IC E
I N ST
RU CTIO N M A
NU A L
Tektronix, Inc .
Ρ . Ο . Box 500
B eaverton, Oregon

97077

Serial N umber
070-1978-00

F
irst Printing SEP
1977
Product Group 48

R
evised APR 1985

Co p y r ig h t f1977 Tek tronix, Inc
. All rig h ts rese r ve d .
Contents of t h is pub licatio n
may
not
be re produced i n any
form wit h out t he written permissio n
of Tek tr on
ix, I n
c .
Products of Tek tronix, I n c .
and
its
su b sidiaries are covered
by U .S . and foreign patents an d /or pen
d
ing
pate
nts
.
TEKT R O N IX, ΤΕΚ , SCO PE-M OB I LE,
a
n
d

a r e
registe r ed trademar k s of Te k tronix, Inc . T ELE
Q U
I PMEN T
is α registere d t r adema rk of Te k t r onix
U .
K . L
imited .
Pr i n ted i n U .S .A . Sp ecification an d price
ch ange p
r
ivileges
a r e r eserved .
IN
ST RUMEN T S ER IA L NUMBER S
Eac h instrument h as α serial n um b er on α par)el insert, tag,
o
r
stampe d on t
he
ch assis . T h e first num b er o r lette r
d esignates t
he cou
ntry of man u fact ur e . T he last five digits
of t h e serial
n
um b er are assigne d seq u entially a nd are
u n
i que
to eac
hinstru
m e n t . T h ose manufact u re d in t he
United States have six un i qu e digits . T h e cou n try of
manufacture is i d entifie d as follows :
ΒΟΟΟΟΟΟ

Te k tro n ix, I n c ., B eaverto n , Oregon,
USA
100000

Te k tro n ix G u er n sey, Ltd ., C h ann el Islan
d s
200000

Te k t r o n ix Un ited K i n gdom, L
td ., L
on
d
on
300000

So n y/Te k t r o n ix, J ap a n
700000

Te k t r onix Hollan d , NV, Hee r e n vee n ,
T he Net h erla n ds

TABLE OF
CONTENTS
P age
SE CTIO N 1

S PE CI F ICATIO N
1-1
SE CTIO N 2

O PER ATI NG I NFO R M ATIO N

2-1
SE CTIO N 3

CI RCU IT D E SC R I P TIO N

3-1
SE CTIO N 4

M AI N T EN A NC
E 4-1
I n t r odu ctio n 4-1
PREVEN TI VE M AI N T ENANC E

4-1
Ge n eral

4-1
Clea n i n g

4-1
Lubr icatio n
4-1
V isual I n s p ection

4-1
T r
a
n
sisto r s a nd I nteg r ated Ci r cu its

4-1
R ecal ib r
atio n

4-1
TR O UBLE S H
OOTI NG

4-2
I n t r odu ction
4-2
T r ou bles h ooti n g Equ i pm e n t

4-2
T r o ub les h ooti n g Aids

4-2
Access to Ci r c u it B oa rd s

4-2
R emovi n g t he V ertical P reamp a nd F ee db ac k Amplifie r B oar ds

4-4
Re m ovi ng and R e p laci n g t heF ee
dbac
k a
nd
V
ert
P
reamp
B oar ds f r om Cam-Switc h Assem b ly

4-6
Cam Switc h R
e p ai
r
a nd
R
e p laceme n t

4-6
R e m oval of Sto r age
Co
mp art m en t
S
h iel d s

4-8
R emoval - R ig h t
Sh
iel d 4=8
R e m oval - L eft S h iel d 4-8
R e p lacement of Sto r age Compartme n t S h iel d - L eft Si de

4-9
R e p lace m en t of Sto r age Comp art m e n t S h iel d - R ig h t Si d e

4-10
SE CTIO N 5

PERF O RM A NC E CHEC K /AD JUST MEN TPR OC ED URE

5-1
I n tro du ctio n 5-1
Services Availa b le

5-1
Test Equ i p me n t R e qu i r ed

5-1
P
erfo r ma n ce C hec k 5-2
A dju
st
m en t Pr
oce dur e

5-12
S E CTIO N 6

REPL AC E A BLEELE CT R ICA L P A R TS
SE CTIO N 7

SC HEM ATIC DIAG R A M S & CI R CU IT B OA R D I LLU ST R ATIO N S
SE CTIO N Β

REPL AC E A BLE ME C HAN ICA L P A R TS & I LLU STR ATIO N S
C H ANG E
I
NF O RM ATIO N
178 Service

178 Service
Fig
.
1-1
. 178 Linear Integrated Circuit Test Fixture .

SPECIFICATION
Sectio n
1-178 Service
Int r od u ctio n

Th e vertical d eflectio n factor switc h h as 28 positio n s
r
a
nging
fr o
m
50 ρ /Div to 50 m/Div ( un mag n ifie d ) in a 1-2-5
se q ue nce . All 28 p ositio ns a r eu
se d
for cu rre n t
T he 178 L i nea r IC Test F ixtu r e is α plug-in device for

m easu r eme n ts, b ut only t he r a nge f r
om
10
μ
/Div
to 50
use wit h t he 577-D1 or 577-D2 Curve T r ace r Syste m s . T he

m /Div ca nbe use d fo r voltage meas u reme n ts . Any attem p t
577-178 combi n atio n , wit h t h e D1 Dis p lay Un it module, is

to m eas ur e voltage u si n g vertical d eflectio n factors less
design ed to measu
r
e t
hepa r
a
m
ete
r
s of o pe
r
atio
n
al

t h a n10 μV /Div ( un mag n ifie d ) ca usest heV O L TS indicator
am p lifiers,

com p arators,

d iffere n tial

a mp lifie r s,

and

lig h t to t u r n off, in
d
icati n g
an u
nusab
le
switc
h position
.
regulators . T he D2 Disp lay Un it may be use d , but lac k i ng
d is p lay storage, t he r esults may n ot b e satisfactory
b ecause of t h e low fre q ue n cies n ecessary to test m any

Vertical d eflection factor is i ncreasedby te n w hen t he
devices .

V ertical P OSITIO N Χ 10 VER T M AG kn ob on t he 577 is
pu lle d
to
t h
eo
u twa
rd position
;
t
he
i ncrease is in d icate d by
t h
e lamp b e h i nd t h e VER T UN ITS/DI V k nob sk irt . T h is
The 178 L i near IC Test F ixt ur e feat ures α swee p lam p
also tur ns off if an u nusable switc h p ositio n is
generato r , p ositive a nd n egative s upp lies, p a rt of t he

selected .
vertical meas u ri n g system, α fee db ac kloop for t h e Device
Und er
Test (D
U
T), a nd switc h i n g ca pa b ilities to facilitate
testi
ng
of vario u s
paramete r
s
und er d iverse
co
nd itio ns
.

ΑFUN CTIO N selecto r switc h pr ovi d es eleven test
p ositio ns . All p ositio n s a r e usef u l to test o p e r atio n al
amplifie r
s .
T he swee p ge n erator provi d es α varia b le freq u e n cy,
0 .01
H
z to
1 kH
z
sin
u soi
d al
o u
tp u t . T h
is o u
t pu t
is use d to
force t
he D
U
T
o u t pu
t
orthe positive a nd
negative
su p p
lies

H
orizontal deflection facto r s range from 50 mV /Div to
(eit he
r in-p h
ase or o
u t-of-p h
ase), or to
swee p t he D U T

200 V /Div
(u
n
magnified), a nd a r e selecte df
r
o
m
t he
i np uts .

CO LLE CTO R V
O
L
TS
seg m
en t of t he 577
H
O
R IZ
V O L TS/DI V switc h .
The do voltage levels of
b
ot
h p ositive an d negative
su p
plies are i nd epen d en tly adju sta b le fr om 0 to 30 volts .
T he n egative s upp ly am p lit ude can b e m ad e to t r ack ( h ave
t he same a b sol u te val ue as) t h ep ositive su pp ly a mp litu d e .
T he maxim u m cu r r e n t ca pa b ility of t h e p
ositive
a
nd
n egative s u pplies can
b e limite d by p oten tio m ete r s on t he
D
U
T ca rd . If t h e loa d c u r r en t atte mp ts to excee d t h e set
li m its, t h e su pply cu rre n t limits a ndα lam p fo
r
eac
h
sup p
ly
i n dicates t h e co nd itio n .
Any
pair (of fo u r p airs) of i n te rn al sou r ce r esistors can
be
use d in series wit h t he am p lifie r i np uts . A n y value of
exte rn al sou r ce r esista nce can b e a dd ed to t h eDUT ca r d .
T h e D U T out p ut can be loa d ed wit h one of sevenvalues of
inter n al loa d r esista nce . Any value of
exter n al loa d
resistance can b e a d de d to t h eD U
T
card
i n pa r allel wit h
t he 50 k Ω of r esista n ce pr
ovi
d ed on
t h e card .
T he vertical m eas u rement system is ca p able of measur-
i n g eit he r voltage or cu rrent . T h ec h oice of voltage or

T he store d d isplay on t h e D1 Disp lay U nit is erased
cu rr en t m easu reme n t is d etermi n ed by
t he
p
ositio n of t he

w
h e neve rt he FUN CTIO N switch is changed , exce p t w hen
FUN CTIO
N switc h a nd is i nd icated by t h e AMP S or

switc h i ng b etween +I NPUT Ι
an d -I NPU
T Ι, + PS RR
and
V O L TS lamp .

-P
S RR, and +S UPPL Y Ι
a nd -S UPPL Y Ι .
T he Sta nd ard Op Am pcar d can b e u sed to test si n gle,
du al, andqua d ope r atio n al am p lifiers . It can also b e use d
to test
si
ngle a
nd du al comparators an d d
ifferential
a mp lifiers . R eg u lator card s are u se d to test t hr ee-terminal
reg u lator p arameters . T hese r eg u lator cards a r e optio n al
accesso r ies a nd a r e cove r ed on se p arate d ata sh eets . IC
soc k et- p in config u rations m u st be connecte d to t hecards
b y u si
nga
da p ter soc k ets an d p atc h co r ds .
An offset Z ER O bu tto n provides αzero crt display
reference an d n ulls offset voltage fo r certai n
m easu r e m en ts t h at would ot he r wise be off sc r een . Offset
is usually r eset auto m atically w h en t h e setti ng of t he
FUN
CTIO
N
switc h is chan ge d . Offset must b e r eset
ma n ually w
hen switc h i n g b etwee n 1 a nd .5 mV /DI V a nd
betwee n .1 mV and 50 μ V /DI V .

S p ecification-178
Service
The elect r
ical cha r acteristics i n t he followi n g table are

Items listed in
t
h
eP erfo r ma nce R eq u ire m e n
ts col u mn
vali d
only
if t h e i n str u ment h
as b ee n calibrated at an

of t he E lect r ical C ha r
acte r istics are verifie d by com p leting
am b ie n t tem pe r at ur e b etween +20° C an d
+30° C, and t
he

t h eP erformance
C
h
ec k i n t h is ma nu al . Items liste d in t he
i n
st r ume n t

is

o p erati n g at an

am b ient tem p erature

S upp leme n tal I n fo rm atio n
column a r e n ot ve r ifie d in t h
is
b etwee n
O' C a nd +50 0 C ( u nless ot herwise n ote d ) .

m a nu al ; t
hey are eit h e r exp la n atory notes o
r pe r forma nce
ch aracteristics
fo r w h ic h no limits are s p
ecifie d .
V ertical
Deflection
Facto r s
I npu t C u rrent ( Ιη

50 ρΑ /DI V to .2 mA/DI V i nα 1-2-5 se
+I np
ut Ι a nd -Inp u t Ι

q ue n ce, u nm ag n ifie d .
F un ctio n s
Accu r acy'
V oltage"
C h aracteristic
C MRR Fun ction
Accu
r
acy
PS
RR Fu nctio n
Accuracy
Ta b le 1-1
ELE CT R ICA L C HA R
ACT ER ISTICS
P erformance R e q ui r eme n t
5 ρΑ /DI V to 20 μΑ /DI V wit h 10 Χ m ag n ifier
on .
W it h in
t3°/ ο ±50 ρΑ , u n mag n ified .
W
it
h
i n t4°/ ο ±50 ρΑ w it h 10 Χ m ag n ifie r
on .
10 μ V /DI V to 50 m V /DI
V i n α 1-2-5 se-
quen ce, un mag n ified .
1 μV /DI V
to 5 mV /DI V with 10 Χ mag n ifier
on .
GAI Na nd
O
FF
S ET V

W it h i n f3°/ ο , u nmag n ified
; f4°1 ο wit h 10 Χ
F un ctions Acc ur acy'

~
m ag n ifie r on .
Within ±3° k +

G~
ΟΟΚ Κ

%+150
μ V Ν .
Within ±4°/ ο +

G
αΊη
0 Κ
Κ

° ο ± 1 Κ μ V
Ν , .
wit h10 Χ
m ag n ifier
on (1 μV /DI V to
5 μV /DI V ,
see foot n otes
b a nd ε ) .
W it h i n t3°/ ο +

100
Κ

°/
ο
Gain - Κ
W it h i n t4°/ ο +

100
Κ

% with 10 Χ
Gai n - Κ
mag
n
ifie r on (1 μV /DI V to 5 μ V /DI V ;
See foot n
otes b
an
d ε ) .
'Acc ur acies a r e t he h ig h est p
erce n tage of on-screen val u es .
'V ertical m ag n i ficatio n is
not
r eco mm
ended fo r .5 m V /DI V t hr oug h 50 mV /DI V
unmag n ifle d setti n gs .
S u p p le m e n tal I n fo rm atio n
`D U T gai n w it hs m all voltage sig n al o u t n ea r ze r
o
wit h50 k Ω
loa d :
Κ =10 f o r 50 m V /Div to 1 m V /Div, Κ =100 fo r .5 m V/D i v to 100
μ
/Div, and
Κ =1000 fo r 50 μV /Div to 10 μV /Div . V
c m =Common-
mode voltage .

Cu rr en t
V oltage
Cu rr en t
Am p lit ude
C
h
aracte
r istic
P owe r Supp ly
Cu
rr
en t
Curre n t M od e
Accuracy'
Collector Su pply
Curre n t M
od
e
Acc ur
acy'
P ositive a nd N egative
S u p p lies
Accu r acy
Swee p Ge ne r ato r
Fr
eq ue
n
cy
Accuracy
In O FF SE TAN
D
GAI N Fun ctio ns
Commo n -mo d e V olt-
age i
n INPU T Ι an d
C MRR
Fun ctions
P owe r Supp ly V olt-
age i
n P S RR a nd
S UPPL
Y Ι F u n ctions
Manual Swee p
At least 150 mA
P erfo r ma n
ce
R e qu ireme n t
1 ηΑ /DI V to 50 mA/DI V in α 1-2-5 se-
qu e n ce, unmagnified
. 0 .1 ηΑ /DI V to
5 mA/DI V wit h 10 Χ mag n ifier
on .
W it h in t3°/ ο t1 ηΑ u n mag n ifie d ; +4 ο/ο
t1 ηΑ wit h 10 Χ mag n ifie r on .
1 ηΑ /DI V
to 50
mA/DI
V in α 1-2-5 se-
qu en ce, u nmagnifie d . 0 .1 ηΑ /DI V
to
5 mA/DI V wit h 10 Χ magnifier on .
W
it
h i n
±3° k t1
ηΑ ,
u nmagnified . ±4%
t1 ηΑ wit h 10 Χ m ag n ifie r on .
A dju sta b le from 0 to 30 V .
W
it h
i
n t2°/ ο ±100 mV .
0 .1 Hz to 1 kH z, si n usoi d al sig n al . F ive
r an ges, 0 .1, 1, 10, 100, and 1000 H z wit h
Χ
.1 to
Χ
1 va r iable .
Wit h i nt5°/ ο
in cali br ate d ( Χ 1) positio n .
0 V to 30 V t3°/ ο maximu m peak . In t h e
1 m V /DI V to 50 m V /DI V ranges, t he
values a r e 10 ο / ο lowe r .
'Accu r acies a r e t he h ig h est pe r cen
tage of on-screen val u es .
Ta b le 1-1 (co n t)
ELE CT R ICA L C H A R ACT ER ISTICS
S p ecificatio n
-178 Se r vice
Su pp le m e n tal I n format i on
B ot h s upp lies εαη b e a dju ste d from t he
+SUPPL Y co n tr ol . N egative su p p ly can
be in d epen d ently a dju sted usi n g t he υη -
cali b rate d -SUPPL Y cont r ol .
T h e-S UPPL Y voltage
is
wit
h i n f1 ο/ο (abso-
l u te) of the
+S
UPPL Y
voltage
w hen
t he
-SUPPL Y co n t r ol is i n t h eTR AC K +S UPPL Y
position .
Ad j ustable cu rr e n t limiti ng .
Ra
n ges overla p at Χ .1 en d of va r ia b le .
A dju sta b le from O V to 30 V t3°/ ο maxi m
u
m
Ad j ustable, de p en ds on f un ction .
T he
voltage
pea k

s hould be limited
to
t h e out p
ut cap
ability
of t he D U T .
L imite d to t he powe r s u pply voltages (clip pe d )
See P ositive and N egative Su pplies
T he
Ge
n
eratoro u
t
pu
t
may b e
man
u
ally
set to
any do level ( un cali b rate d ) wit h i n its ampli-
t ud e range ( d epen ds on t he setti ng of t he
FUN CTIO N switc h ) .

Sp ec i ficat
i on-178 Service
Ta b le 1-1 (co n t)
ELE CT R ICA L C HAR
ACT ER ISTICS
C ha r acteristics

P erforma n ce R eq uire m en t

S upp le m e n tal Info r mat i on
So u rce R esista nce
R esista n ces

I

I

F ou r p ai r s ; 50 Ω ,10 k Ω ,
20
k Ω ,
a
n
d 50 k Ω .
Tolerance

Ι

Ι f1°/ ο ±10 Ω .
L
oa d
R
esista n ce
Wh en t he VER T UN ITS/DI V
switc h is setto
1 m V /DI V t hr oug h 50 mV /DI V ,
t h e i nd icate d
val u es i n crease by 500 Ω . Exte rn al resis-
tors ca n be use d .
R esista n ces

Seve
n
R esistances ;100 Ω ,1 k Ω , 2 k Ω , 5 k Ω ,
I

~

10 k Ω ,
20
k Ω ,
an d 50 k Ω .
Tolerance

f3°/ ο except w h en usi n g t he 50 m V , 20 m V ,
a nd
10 mV p ositions of t he VER T UN ITS/DI V switch .
T h e tolerance fo r t h e 50 k Ω t h e n b ecomes±30%,
fo r t h e 20 k Ω ±14%,10 k Ω t7"/ ο , an d 5 k Ω f3°/ ο
w he n t h
e
D
U
T
out p ut voltage swin g is 2 .5 V o r
less . T he m axi m u m tolerancedecreases ex
p o-
n e n tially as t he ou t p ut swing
is
i
nc
r
eased
a nd is less t ha n t3°/ ο w h en t he out
p ut is
swin gi n g ±30 volts .
Ta b le 1-2
ENV I
R O NMEN TA L C HA R ACT ER ISTICS
C h a r
acte
r
istic

P erformance R
eq ui r e m e n t

Ι

S u ppleme
n tal
Tem p eratu r e
S
p ecified O pe r ati ng

Ι

Ι

+10° C (+50° F)
to
+40°
C (+104° F)
U sef u l O pe r
ati ng

Ι

Ι

0° C (+32° F) to+50° C
(+120° F)
Non-operating

Ι

Ι

-40° C (-40° F) to +65° C (+149° F) .
Altitu d e
Operatin g

Ι

Ι

To
10,000 feet (3000 metres)
Tra n sportatio n
12-i n ch (30 cm) p ack age d
rop . Qualified u nd e r
t he N atio n al Safe Tra n sit Co mm ittee
pr oce du re
1 Α .

Di m ension s
H eigh t
W i d t h
De p t h
W eig h t
N et
Table 1-3
PH YSICA L CH AR ACT ER ISTICS
4 .5 i nches (11 .4 cm)
7 .9 i nches (20 .1 cm)
7 .8 inc hes (19 .8 cm)
3
.3 p
ounds (1 .5 k g)
STA N DA R D ACC E SSO R I E S
R efer to t he R ep laceable M ech a
n
ical
P
arts
list fo r α listi ng of t h e sta n da r d accessories .
S p ecificatio n -178 Service

Int r od uction
T he 178 Test F ixt u re
operates wit hα T EK T R O N IX 577

+S UPPL Y, -S UPPL Y
C u rve T r ace r a nd t he D1 or D2
Display Un it as α system .

There
are
two a dj ustable, r egulate d s upp lies, on e
p ositive an
d
one negative, in t
h
e 178 . T h ea dj ustme n t
ra n ge is 0 to
30 volts,
wit h
150
mA
cur
r
e
n t
ca pa b
ility .
T h is
sectio n of t h e ma n ual gives α b rief f
u nctio n al

A dju stable cu rr en t limiti n g fo r eac hsu pp ly is pr ovi ded
on
d esc r i p tio n of t he fro n
t-panel co n tr ols of t h e 178
. See t h e

t he Device Ca rd . Ove r loa d la mp s i n t he s upp ly-co n t r ol
577-178-D1 or D2
O pe r ato r s Manual fo r αco mp
lete

area i n dicate w h en t h e cu rr e n t li m it is reac h ed .
o pe r ati ngproce d
ure .
Pr
eliminary
F or i n itial p r e pa r
atio n , r efer to t he
Operating
I n st
ru c-
tio ns sectio n
of t he 577-178-D1 o r D2 O p erators
Manual . T he O p erators
Manualco n tai ns op erating i n-
str
u ctio n s, as well as ge n eral
an d sp ecific application
i n
for
m
atio n .
T h is is α b rief d escri p tio n of t h e fu n ctio ns of t h e f r on t-
pan el co n t r ols . M o r e detailed i
n
fo
rm
atio
n
is
given i n t he
O pe r ato r s Manual .
FUN
CTIO N Selector
O PER ATI
N G I NF
O RM ATIO N
SO URC E RE SISTA N C E
CON TR O L S

L OAD RE
SISTA NC E
Sectio n 2-178
Service
T h is switc h selects on ep air of fo ur i npu t r esistors p airs :
50 Ω (550 Ω w he n VER TUN ITS/DI V is i n t h e 1 m V
to
50
m V /DI V range), 10 k, 20 k, o r 50 k . E xter n al r esistances
may b e selected i n t h e ΕΧΤ p ositio n .
T h is switch selects on e of seven
loa d resistors : 100 0, 1
k,
2
k,
5 k, 10 k, 20 k, o r 50 k . E xter n al r
esistance m aybe
selecte d i n t he ΕΧΤ p ositio n .
T he eleven
-position FUN CTIO N switc h selects t he

μΕ RΤUN ITS/DI V
p oints
to be monitored by t he vertical an d h o r izo n tal
d is p lay axes, a nd
selects t he p oi n t d riven b y t he Swee p

T h is switc h selects t he ve r tical d eflectio n factor . T he
Ge n erator .

d eflectio n factor is eit h er voltage or cur re n t p e r d ivisio n ,
d e pen di ng on t he FUN CTIO N switc h positio n . I nd icator
lamps sh ow eit he r V O L TS or A
MP
S .
T
hevoltage mea nu re-
S WEEP FRE Q UEN CY

m ent r ange is 10 μ V /DI V to 50
m V /DI V ( μ V /DI V wit hΧ 10
A dj usts t h e
Swee p Gene r ato r f r eque ncy f r o m .01 H z to

ve
r
tical
mag n ifie r
on) .
T he
cu
rr en t measureme n t ra n ge is
1 kHz . F ive cali
b rate d fre q uency ste p s, .1,1,10,100, a nd 1

50
ρΑ
/DI
V to 50
m A/DI V
(5 ρΑ
/DI V wit h Χ 10 vertical
m ag n ifie r
on) .
kH z, are p rovi d e d . T he V A
R IA BLE co n t r ol pr ovi d es con -
ti nuo u s a dju stment f r o m .1
to
1
.0
times
t h e selecte d
d eca de val ue .
DEV IC E CA R D
S WEEP A MPL IT
UDE

T he Device Ca rd p rovi
d es test co n fig ur atio ns most
su ite d to seve r al classes
of d evices
.
Device Ca r ds p rovi d e
Ad j usts t h e Swee p
Ge
n
erator amplit u d e from zero volts

α
mea ns of m ak i n g electrical
con
n
ectio n s to t h e D U T
to its m axim u m val u e (wh ic h d ependson
t he functio n (
d evice
u n de r test), a nd in most
cases, also pr ovi d e some
b ei n g swept b y t he Sweep
Generator) .

circuitry .

CO LL E CTO R
SUPPLY
(G r o up
4)
R E G U L AT E D
P O W E R
S UPPL I E S
(G r oup 3)
SWEEP
G ENER ATO R
(G r oup 2)
ID E N TI F ICATIO N
O
F
CO
NTR
O LS
νι

αιε εοιιεαοπχ

mo

υ
π
1-

ι
_VOLTS

Γ -

αι ,ο . α,α
εοιινό ,
ρτνννιν
Ι
ιι
ρτε
~~~ ~
6ε

'

s τοπα
Ιεαα
CO
L
L
E
CTOR S
U
PP
L Y
-577_- εΑ

I-
ΑΡ 4 .
P O WER, L OADS,
--SO UR C E RE SISTO
RS
-

(G r o u p 6)
D EV IC E
CA R D
1 ) 1 ι O78TORAGE
W

τ1

εετεΤ r υι :
STEP GENERATOR
Ο Ο Ο Ο Ο Ο
F ig . 2-1 .
178 Fr o n t- pa n el co n t r ols .
,78 .-°
;
.
;ά ,
Op erati
ng Infor m atio n
-178 Service
C R T
CO N TR
O LS
(G r o up 8)
STEP
GENER ATOR
(G r oup 5)
DEFLE CTIO
N
CO N T RO L S
(Group 7)
FUN CTIO N
S ELE CTO R
(G r oup 1)
D E F LE CTIO N
CO N T R O L S
(Gro up 7)
1474-09

CI R C U
IT D E
SCRI
P TIO N
T h is section of t he 178 Service
Manualco
n tai ns
t h e
d esc r iption of t he 178 L i nea r Test F ixtu r e . Wh ile usi n g t h is
d escription, r efe r to t h e ill u st r atio ns wit h i n t h is sectio n ,
an d
to t
h
e Switch i n g B loc k Diag r am a nd t h e circ u it
d iagrams in t he
foldout p ages at t he r ea r of t h is ma nu al .
R
efer to F ig . 3-1 . In t h is test, t h e Swee p Ge ne r ator is fe d
T he 178 L i n ea r Test F ixt ur e is designed to perfo r m α

in at t he i n p
ut of t h e F ee db ack Am p lifie r , forci n g t h e
mu lti p licity of tests, some of w h ic h d iffe r wi d ely .
As
α

Device U
nder Test (D U T) out pu t . T h is is fe d to a nd
r
esult, t he ci r cuit d escri p tio n is d ivi d ed i n to two ma j or

d isplaye d by t heH o r izo n tal Amp lifie r .
At t he same time,
p a r ts, t h
eF un ctio n Description an d t he Detaile dCi r cu it

t h e V ertical Am p lifie r dis p lays t he r esultant diffe r e n tial
Desc r i p tio n .
In
t he first, t he 178
is d escri bed , for eac h
voltage
at t
he
in p ut te r minals of t h e D U T . N ote t h at t he
fu n ctio nswitch position, in t he
way
t he
ma j o
r
ci r cuits

Sam p le & H
ol d Am p lifie r is n ot co nn ecte d i n t h e circ u it ;
wor k toget h er . In t h e seco nd , eac h
of t
h
e ma
j
or ci
r
cuits is

ot h erwise,
t
h
e Sa mp le
&
H old ci r cuit wo u l d h ave compe n -
descri bed i n d etail .

sated for t he
d iffe r en tial voltage .
FUN CTIO N
SWITC H
R SOURCE
POSITIVE
PO W ER
S UPPL Y
SWEEP
G EN
D U T

FEE D B AC K
-VI-1-l d ~~ 7
AMP
R SOURCE

R L OAD ~ 7 1
H O R IZ
' ΑΜΡ
NE GATI V Ε
P O WER
S UPPL Y
SA MPLE
H
O L D
O
FF
S E T V O L TS
FUN
CTIO
ND
E SC R I P TIO N
FUN
CTIO N
SWITC H
01111111111111100
Fig . 3-1 . B loc k d iagra m
of O
FF
S
E T V
co n fig ur atio n .
Sectio n
3-178
Serv i ce
VER T
AMP
1474-16

Ci r cuit Desc r i p tio n -178 Service
+ INPU T Ι
H O R IZ
AMP
DU T

FEE D B AC K
" °

AMP
r
ιΙν
CO NY
NE GATI V
P O WER
S UPPL Y
ΡΙΟ
ZER
O --

!
RE SE T
SA MPL
E
S W
E EP
G EN

HO L D
POSITIVE
P O WER
S
UPPL Y
F ig .
3-2 . B loc k d iag r am of + INPU
T Ι configuration .
147417
R efe r
to
F ig .
3-2 . In t h is test, t h e Swee p Gene r ator
pr ovides avoltage to swee p t h
e i
npu
t of t heD U T, w h ile t he

-
INPUT Ι
i np ut cu rre n t to t he D U T
is measured . T h e swe p t voltage is
d is p laye d by t h e H orizontal Am p lifie r ,
a nd t he r esu lta n t

R efer to F ig . 3-3 . T h
is test is exactly t he same as t h
e o ne
i np ut cu rrent is first processed by t he Ι / V Co n ve r te r , t hen
fo
r +
I NPU T Ι, exce p t t h
at t h e Ι / V Co n verter is tied
to
t he
ap p lie d to t he V e r tical Amplifie r fo r dis p lay on t h e vertical

o pp osite DU T i n p u t, p er m itti n g
t he meas ure m ent of t he
axis .

cu rr en t at t he min us i np ut .

P
OS
P
O WER
S
UPPL Y
R ΕS ΕΤ

SUPPLY
S WEEP
G EN
SA MPLE
J & H
O L D
VER T
DU T

FEE D B
AC K
AMP
1- 100
F ig . 3-3 . B loc kd
iag r a m
of
-
I NPU T Ι
co n fig ur ation .
C
i r
cuit Desc r i p tio n -178
Service
1474-18

Ci r cu it
Description-178 Service
1 :

1
R
r
SO UR C E
Ρ /
Ο

NE G
Z
ER O ---

P O WER
RE SE T

S UPPL Y
SW EEP
G EN
Ι ΗΟ \
P OS

AMP,
P O WER
R

Ι S UPPL Y
1 1
SO UR C E
ι
~ r ν
ιι
DUT

FEE D B AC K
",
Ι Α
MP
SA
MPLE
& H O L D
Ρ / Ο
Z ER O
RE S E T
ι
Ο
- '
Ο
VER T
AMP .
1474-19 Β
C MRR
3- 4
F ig . 3-4 . B loc k d iag r am
ο 1 C MRR
co
nfigu
ratio n .
GAI N
R eferto F ig
.3-4
. 1 η
t h e C MRR mo d e, t he D U T i np uts are

R
efe
r
to Fig .
3-5
. Th e GAI N meas ur eme n
t configuratio n
tied toget h e r t h roug h atte nu
ators, t h en αvoltage is

is similar
to
t h
e O FF SE TVO L TS config u ratio n
desc r ibe d
a pp lied to t he commo n jun ctio n
of t
h
e atte nuato r s f r om

ea r lier, except
fo
r
t h e i n clusio n of t h e
Sa
mp
le
&
H ol d
t he Swee p Ge n erator . T he swee p i n g voltage
is dis p laye d
Circ u it . T he
Swee p Ge n erator o u tput is used to force
t
he
on t he h o r izo n tal axis . T he r esulta n t diffe r
e
n
tial voltage

DU T out
pu t, w h ic h in tu rn is fe d to t he H orizo n
tal
t h at is fe d back to t h e inputs f r o m t he Fee db ack Amplifier

Am p lifier for d
is p lay on t h e h o r izo n tal axis . T h e r
esulta n t
is d is p laye
d on t h e ve r tical axis .

differe n tial voltage
is fed to t h e vertical am p lifie r
for
dis p lay on t he ve r tical axis
.
RE V ΑA PR 1980

R SOURCE
Ι
P
OSITI V

VER T
E
POW ER
S WEEP
Ι

AMP,
S UPPL YG
EN
D U T

FEE D B AC K
AMP
R SOURCE

NE GATI VE

RL
OAD

HO R IZ
SA MPLE
HO L D
ΡΙο
Z ER O
RE S E T
P O WER

ΑΜΡ
ΡΙΟ
S UPPL Y 1
F ig . 3- 5 . B loc k d iag ra m of GAI N co n fig u ratio n .
Z ER O
RE S E T
ι
ι
Ci r cuit Description-178 Service
1474-22

Circuit
Description-178
Service
+ ρ
S
RR
P
OSITI VE
PO WER
S UPPL Y
SA MPLE
H O
L D
Ρ /
Ο
Z ER O
RE SE T
S WEEP
G EN
H O R IZ
AMP
R SOURCE
D UT

FEE DB AC K
ΑΜΡ
ι VER T
NE GATI VE

AMP .
RSO UR C E P O WER
S UPPL Y

Ρ / Ο
ZERO
RE SE T
D
F ig . 3-6 . B loc k
d iag r a m of + PS RR con fig ur atio n .
1 α 7 α -2 ι
R
efe
r
to F ig . 3-6 . T he o bj ective of t h e + PS RR
test is to
divi d e t h e c han
ge i
n p
ower-s u pply voltage by t he ch an ge
i n inpu t voltage r e qu i r e
d to h ol d t he out p ut voltage

- ρS
RR
con sta n t . To d o t h is, t he Sweep
Generato r is co nn ecte d to
swee p t he p ositive p owe r supply ;
t he h o r izo n tal axis

R efe r to F ig . 3-7 . T h is
test is identical to t h e + P
S RR
dis p lays t h is sig n al . T he res u lta n t ch
a
n
ge is sen t to t he

test, except t h at t he minu
s supply is swe p t r at h er t h a n
t h e
V e r tical Amplifier for d isplay on t he vertical axis .

p l us s
up ply .

R SOURCE
RSO URC E
POSITIVE
P
O WER
S UPPL
Y
O UT
FEE DB AC K
---
AMP
HO R IZ
NEGATIVE
P OW ER
S UPPL Y
AMP
Ρ /
Ο
Z ER
O
RE SE T
S ωεΕΡ

ι Ρ /
ο
G EN
Z
ERO
RE
SE T
SA
MPLE
HO L D
D
F ig . 3-7 . B
loc k Dlag r a m of - P S RR
co
nf
ig ur ation .
C i rc u it Desc r i p tio n -178 Service
VER T
AMP
ια 7 α -2 ο

Ci r cu it
Desc r iptio n -178 Service
± P S RR
ΡΙο
ZE R O
RE S E T
P OSITI VE

ι
P
O WER
S UPPL Y
H
O
RIZ
AMP
Ρ /
Ο
Z ER O
R ES E T
S W EEP
G EN
D
U
T

F EE D B AC K
Ι

AMP
Ι
NE GATI VE
POWE V R
Ι
P O WER
VER T
Ι

1 AMP
S UPPL Y
/
Ρ / Ο
SA
MPLE
HO
L D
+
S UPPLY Ι
Z E RO
RE SE T
Fig
.
3-8 . B
loc
kd
iagram of t PS RR
configuration .
1474-23
R efe r to F ig .
3-8 .
T he
±
PS
RR config ur ation is si m ila r to
t he pr evious two tests, except t h at t h
e Swee p Ge n e r ato r

R
efer to F ig . 3-9 . T he p owe r su pp ly voltage is swept
by
ou t pu t is a pp lie d to b ot h t he pl u s a nd minus
su pp lies, an d

t h
e out p ut of t h e Sweep Ge n erator i n t h is configu r atio n .
t h ey a r e swe p t i no pp osite d irections . T he out p
ut of t he

T h
e out pu t of t he p ositive p owe r su pp ly is fe d t hr oug h t h e
p ositive su pp ly is d isplaye d on t he h orizontal
axis, a nd t he

IN Co n verter, t hen t he V ertical Amplifie r fo r dis p lay of t h e
diffe r
en
tial i npu
t voltage to t he D U T is d is played
on
t he

p ower s u pply
c u rrent . T he H orizo n tal Axis d is p lays t h e
ve r tical axis .

swe p t p ower s u p p ly
voltage .