Tektronix 5440 Instruction Manual page 57

Troubles
h
ooting
P
rocedure 7 .
C
h
ec
k
Individual Com p
onents . T
h
e followi
n
g
proce
d
u
r
es describe met
h
od s for c
h
ec
k
i
n
g individ
u
al
1 . C
h
ec
k
Co
n
trol Settings . Incorrect control settings
com p one
n
ts . Two-lead compone
n
ts t
h
at are sol
d
ere
d
in
ca
n
i
n
d icate α trouble t
h
at d oes not exist . If t
h
ere is any
p lace are best c
h
ec
k
e d by first disco
n
necti
n
g o
n
e e
nd .
q uestion about t
h
e correct fu
n
ction or operation of any
This isolates t
h
e measureme
n
t from t
h
e effects of surrou
n
-
control, see
F
ig . 1-1 .
di
n
g circuitry .
2 . C
h
ec
k
Associate
d E
quipme
n
t .
B efore trouble-
s
h
ooti
n
g, c
h
ec
k
t
h
at t
h
e e
q
ui
p
ment used wit
h
t
h
is i
n
str
u
-
me
n
t is p roperly co nn
ected and t
h
at t
h
e interconnecting
cables are not
d
efective . Also, c
h
ec
k
t
h
e p ower source .
3 .
V
isual C
h
ec
k
. V isually c
h
ec
k
t
h
e p ortion of t
h
e
instrument i
n wh
ic
h
t
h
e trouble is locate
d
. Many troubles
T
R
A
N
SISTO
R
S . T
h
e best c
h
ec
k
of transistor operatio
n
ca n
be locate d by visible indicatio
n
s suc
h
as u
n
sol
d
ere
d
is actual performance un d er operating con d itions . Α
con
n
ections, bro
k
en wires, damaged circuit b oard s,
transistor ca
n
be most effectively c
h
ec
k
ed by substituting
d amage d com p onents, etc .
α
n
ew com po
n
e
n
t or o
n
e t
h
at
h
as bee
n ch
ec
k
ed previous-
ly . H owever, be s
u
re t
h
at circ
u
it co
nd
itio
n
s are
n
ot s
u
c
h
t
h
at α replacement transistor mig
h
t also be d amaged . If
4 . Isolate Trou b
le to α Circuit . To isolate trouble to α
substitute transistors are not available, use α dy
n
amic
circuit, note t
h
e trouble symptom . T
h
e symptom ofte
n
tester . Static-ty p e testers are not recommen d e d , si
n
ce
i d entifies t
h
e circuit in w
h
ic
h
t
h
e trouble is located . Wh
en
they d o
n
ot c
h
ec
k
o
p
eratio
n
under simulate d
o
p erati
n
g
trouble sym p
toms a
p
pear in more t
h
a
n
o
n
e circuit, c
h
ec
k
con
d
itio n s .
t
h
e affected circuits by ta
k
i
n
g voltage a
nd
waveform
rea
d
i
n
gs . Incorrect o
p
eration of all circuits often i
n
d icates
trouble i
n
t
h
e power sup
p
ly . C
h
ec
k
first for co
r
rect
I
N
T
E
G
R
AT
E
D CI
R C
U
ITS . IC's can be c
h ec
k
ed wit
h α
voltages of t
h
e i
n
dividual su
pp
lies . See Table 4-1 .
voltmeter, test oscillosco
p
e, or by d irect substitutio
n
. Α
H owever, α defective component elsew
h
ere in t
h
e instru-
good u
n
derstandi
n
g of circuit o
p
eratio
n
isdesirablew
h
e
n
me
n
t ca
n ap
p ear as α power-su pp ly trouble a n
d may also
troubles
h
ooting circuits using IC's . U se care w
h
e
n
c
h
ec
k
affect t
h
e o
p
eration of ot h
er circuits .
ing voltages an d waveforms arou
n
d t
h
e IC's so t
h
at
a
dj
ace
n
t leads are
n
ot s
h
orted toget
h
er . Α convenient
means of cli
p
p i
n
g α test probe to t
h
e 14-an
d
16-pi
n
IC's is
5 . C h ec k V oltages a n
d W aveforms . Ofte
n
t
h
e d efective
wit
h
an 1 C test cli p . T
h
is d evice also serves as an extraction
com p onent can be locate
d
by c
h
ec
k
ing for t
h
e correct
tool .
voltages and waveforms in t
h
e circuit .
6 . C h
ec
k
I
n
strument Ad
j
ustme
n
t . C
h
ec
k
t
h
e a
dj
ust-
5
CAUTION
ment of t
h
is i
n
strument, or t
h
e affected circ
u
it if t
h
e
~.~~r .. . .
trouble a
p
p ears in one circuit . T
h
e a pparent trouble may
Do not use an o
h
mmete
r
scale t
h
at
h
as α high
be t
h
e result of
m
isad
j
ustme
n
t . Com p lete ad
j
ustme
n
t
internal cu
r
re
n
t .
H
ig
h
currents may damage
t
h
e
instructions are given in Sectio
n
5 .
d io
d
e .
200 V
+30
V
+15
V
+5
V
-15
V
-30
V
Ta
b
le 4-1 DIOD
E
S . Α d io
d
e can be c
h ec k e d for an o
p
e
n
or
s
h
orted condition by measuri
n
g t
h
e resistance between
P
ower Su
pp
ly Tolerances
termi
n
als wit
h
an o
h
mmeter scale
h
avi
n
g α low i
n
ter
n
al
source curre
n
t, s
u
c
h
as t
h
e
R
Χ 1 Κ scale . T
h
e resistance
Typical s
h oul d be very
h
ig
h
in one d irection an d very low w
h
en t
h
e
P
ower Su
pp
ly I Tolerance 1 120 Hz R ipple
meter lea
d
s are reversed .
+180 V
to +240
V
2
V
or less
+29 .925
V
to +30 .075
V
2 m
V
or less
+14 .85
V
to +15 .15
V
2 m
V
or less
+4 .9
V
to +5 .1
V
2 m
V
or less
-14 .85
V
to -15 .15
V
2 m
V
or less
-29 .925
V
to -30 .075
V
2 m
V
or less
M
aintenance-5440
To avoid component damage, disconnect t
h
e
p
owe
r
source before removing or replacing semico
n
duc-
tors .
RE SISTO
R
S . C
h
ec
k
resistors wit
h
an o
h
mmeter . See
t
h
e
R
eplaceable
E
lectrical
P
arts list for t
h
e tolerance of t
h
e
resistors used in t
h
is instrument . R esistors nor
m
ally d o
n
ot
n
eed to be re p lace
d un
less t
h
e measure
d
value varies
wi d ely from t
h
at s pecifie
d
.