Tektronix 454A - Page 103

B
ase
~W
Gat e
/ '
. \
Dr ai n
Sour ce
Col l ect or .
Base
E mi t t er
M et al - Case Tr a n si st or s
F i el d - Ef f ect
Tr ansi st or s
D U A L
D UAL
Sour ce
- Dr ai n
Gat e
Col l ect or
Base
Emi t t er
F i g . 4- 2 . E l ect r o d e co n f i g u r at i o n f or semi cond u ct or s
i n
t h i s i nst r
u me n t .
F l at
si de
Base
P l ast i c- Case Tr an
si st or s
Mai nt enance- 454zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA ‘ / R454A
Em i t t er
Em i t t er
Power Tr ansi st or s
Col l ect or
Tr oubl es h oot i ng Tec h ni q ues

3 . C h ec k I nst r ument Cal i
b r at i on . C h ec k t h e cal i br at i on
of t h i s i nst r ument , or t h e af f ect e d
ci r c u i t i f t h e t r o u bl e
T h i s t r o u bl es h oot i n g p r oce d
ur e i s ar r ange d i n an or d er

exi st s i n one ci r cui t . T h e a pp ar ent t r oubl e
may onl y be ±
wh i c h ch ec k s t h e si mp l e t r oubl e p ossi b i l i t i es b
ef or e p r o-

r esul t of mi sa d j ust ment or may b e cor r ect e d by cal i br at i on
.
cee d i ng wi t h ext ensi ve t r oubl es h oot i ng . T h e f i r st f ew

Compl et e cal i b r at i o
n i nst r uct i ons ar e gi ven i n t h e Cal i -
br at i on
ass u r e p r op er connect i on, o p er at i on a n d cal i b r at i on .

br at i on sect i on of t h
i s
man
u al
.
I f
t h
e t r o
u bl e i s not l ocat e d by t h ese c h ec k s, t h e r emai ni ng
st e p s ai d i n l ocat i ng
t
h
e
d
ef ect i ve com p onent . Wh en t h e
d ef ect i ve com p onent i s l ocat e d , i t s
h
oul
d
b
e r e p l ace d
 4,
V i sual C h ec k . V i sual l y
c h ec
k
t h e por t i on of t h e
f ol l owi n g t h e r e p l acement p r oce d u r e gi ven und er Cor r ect i ve

i nst r ument i n w h i c h t h e t r o u bl e i s l ocat ed .
Many t r oubl es
M
ai nt enance .

ca n b e l ocat e d by vi sual i n d i cat i ons s u c h as
u
nsol
d er ed con-
nect i ons, b r o k en wi r es, d amage d ci r cui t boar d
s,
d
amage d
1 . C h ec k Cont r ol Set t i ngs . I ncor r ect cont r ol set t i ngs
can

com p o n ent s, et c .
i n d
i cat e
± t r oubl e t h at does not exi st . I f t h er e i s any q ues-
t i on about
t
h
e cor r ect f u nct i on or o p er at i on of any cont r ol ,
see t h e O p er at i ng I nst r uct i ons
sect i on of t h i s manu al .

5 . I sol at e
Tr oubl e t o ± Ci r cui t . To i sol at e ± t r o ub l e
t o ±
ci r cui t , not e t h e t r o u bl e
sym p t om . T h e sym p t om of t en
i d ent i f i es t h e ci r cui t i n w h i c h t h
e t r ou b l e i s l ocat ed . F or
2 . C h ec k Associ at e d E q ui p ment . B ef or e p r ocee d i ng
wi t h  exam p l e, p oor f ocus i n d i cat es t h at t h
e C R T ci r cui t ( i n-
t r oubl es h
oot i ng of t h e 454 ‘ , c h ec k t h at t h e eq ui p ment

cl
u d
es
h i g h vol t age) i s pr o b a b l y at f a u l t .
Wh en t r o ub l e
u se d wi t h t h i s i nst r u ment i s o p
er at i ng cor r ect l y . C h ec k t h at

sympt oms
a p p ear i n mor e t h an one ci r cui t , c h ec k
al l t h e
t h e si gnal i s p r o p er l y connect e d an d t h at t h e
i nt er con-

af f ect e d ci r cui t s b y t a k i n g vol t age
an d wavef or m r eadi ngs .
nect i ng ca b l es ar e
not
d
ef ect i ve . Al so, c h ec k t h e p ower

Al so c h
ec
k
f or t h e cor r ect o u t p ut si gnal s
at t h e out pu t
so u r ce
.

connect or s wi t h ± t est osci l l oscope . I f t h e
si gnal i s cor r ect ,
4- 5