Tektronix 454A - Page 108

M ai nt enance- 454zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA ‘ / R 454A
T h e
f ol l owi ng t ec h ni q ue s h o u l d be u se d t o r e p l ace ±

Obser ve t h e f ol l owi ng p r ecaut i ons w h en sol d er i ng t o
component on ± ci r cui t boar d
. M
ost com p
onent s can be

cer ami c t er mi nal st r i p s .
r e p l ace d wi t h o u t r emovi ng t
h
e
boar ds f r om t h e i n st r u ment .
1 . U se ± h ot i r on
f or ± s h or t t i me . Appl y onl y enoug h
h eat t o ma k e t h e sol d er f l ow f r eel y .
1 . Gr i p t h e com p onent l ea
d wi t h l ong- nose
p
l i er s .
To
u c h
t h e
sol
d
er i ng i r on
t o t
h e l ea d
at t
h e sol d er co n nect i on . Do

2 . M ai nt ai n ± cl ean, p r o p er l y t i nne d t i p .
not l ay t h e i r on d i r ect l y on t h e boar d, as i t may d amage t h e
b oar d .

3 . Avoi d p ut t i ng p r essur e on
t h e cer ami c t er mi nal st r i p .
4 . Do not at t em p t t o f i l l t h e t er mi nal - st r i p not c h wi t h
2 . Wh en t h e sol d er begi ns t o mel t , pul l t h e l ea d o u t

sol d er ; use
onl y
eno u g h sol d er t o cover t h e wi r es a d e
gent l y . T h i s s h oul d l eave ± cl ea n h ol e i n t h e boar d . I f not ,

quat el y .
t h e h ol e can b e cl eane d by r e h eat i ng t h e sol d er an d p l aci ng
± s h ar p ob j ect suc h as ± t oot h p i c
k
i nt o t h e h ol e t o cl ean i t

5 . Cl ean t h e f l u x f r om t
h
e
t er mi n al st r i p wi t h ± f l u x
out . ‘ vacu u m- t y p e
d
esol
d
er i ng
t ool can al so be used f or

r emover sol vent .
t h i s p u r pose
.
M et al Ter mi nal s . Wh en sol d er i ng met al
t er mi nal s ( e . g . ,
3 . B end t h e l ea d s of t h e new com p onent t o f i t t h e h ol es

swi t c h  t er mi nal s,

p ot ent i omet er s,
et c . ) , or d i nar y 60/ 40
i n t h e boar d . I f t h e com p onent i s r e p l ace d wh i l e t h e
b
oar
d
 sol d er ca n be use
d . U se ± sol d er i ng i r on wi t h ± 40- t o 75-
i s mount e d i n t h e i nst r ument , c u t t h e l ea d
s so
t h
ey
wi l l j ust

wat t r at i ng
an d ± 1/ 8- i nc h wi d e wedge- s h a p ed t i p .
p r ot r u d e t h r o u g h t h e b oar
d . I nser t t h e l ea d s i nt o t h e h ol es
i n t h e boar d so t h e com p onent
i s f i r ml y seat e d agai nst t h e
Obser ve t h e f ol l owi ng
( or as p
osi t i oned or i gi nal l y) . I f i t d oes not seat pr op -

ng pr eca
u t i ons w h en sol d er i ng met al
t er mi nal s :
h
eat t
h e sol der an d gent l y p r ess t h e com p onent i nt o

nal s :
p l ace .

1
. Appl y
onl y
enoug h heat t o ma k e t h e sol d er f l ow
f r eel y .
4 . Touc h t h e i r on t o t h e connect i on
an d appl y ± smal l
amount of sol d er t o ma
k
e
± f i r m sol d er j oi nt . To p r ot ect
h eat - sensi t i ve
com p onent s, h ol d t h e l ea d b et ween t h e
com p onent bo d y an d t h e sol d er j oi nt wi t h ± p ai r of l ong-
nose
p
l i er s or ot h er h eat si n k .
5 . Cl i p
t h e excess l ea d t h at p r ot r u d es t h r oug h
t h
e
boar d
( i f not
cl i pp e d i n st e p 3) .
6 .
Cl ean t h e ar ea ar o u n d t h e sol d er
connect i on wi t h ±
f l u x- r emover sol vent . B e car ef u l not t o
r emove i nf or mat i on
p r i nt ed on t h e boar d .
4- 1 0
2 . Appl y onl y enoug h sol
d
er
t o f or m ± sol i d connect i on .
E xcess sol d er may
i m p ai r t h e f unct i on of t h e p ar t .
3 . I f ± wi r e ext en d s beyond t h e sol d er j oi nt ,
cl i p of f t h e
excess .
4 . Cl ean
t h e f l ux f r om t h e sol d er j oi nt wi t h ±
f l ux-
r emover sol vent .
Component R ep l acement
WARN I NG
Di sconnect t h e i nst
r ument f r om t h e power sour ce
bef or e r e p / aci ng
component s .
Cer ami c
Ter mi nal St r i p s . Sol d er u se d on t h e cer ami c
t er mi nal
st r i p s s h oul d co n t ai n a b out 3% ¿ si l ver . U se
±
40- t o
75- wat t sol d er i ng i r on wi t h ± 1/ 8- i nc h wi d e we
d ge- s h a p ed

R emovi ng t h e R ear Panel . T h e r ear
p anel m u st be r e-
t i p . Or
d i nar y sol d er can b e u sed occasi onal l y
wi t h o u t dam-

moved f or access t o t h e r ear sub p anel
. T h i s p anel can be
age t o t h e cer ami c t er mi nal st r i p s . H owever ,
i f or d i na ry

r emove d by r emovi ng t h e – Axi s
gr o
u
n d st r a p an d t h e
sol d er i s used r e p eat edl y or i f excessi ve
h eat i s a p pl i e d , t h e

scr ews t h at secur e t h e i nst r ument f eet t o t h
e
r ear
cast i ng .
sol d er - t o- cer ami c b on d may be
br o k
en
.
R emovi ng t h e
R ear Cast i ng . An al t er n at i ve met h od
f or
‘ sampl e r ol l of sol der cont ai ni ng a
b out 3% si l ver i s

gai ni ng access t o
t h e r ear su b p anel i s t o r emove t h e r ear
mo u nt ed on t h e r ear
s
u
b p anel of t h i s i nst r ume n t . A d d i -

cast i ng
f r om t h e i nst r u ment . T h i s i s easi l y accom p l i s h
e d by
t i onal sol
d
er of
t h e same t y p e s h oul d be avai l a b l e l ocal l y, or

r emovi n g t h e f our f l at - h ead ph i l l i p s scr ews
t h at sec u r e t h e
i t
can be p u r c h ase d f r om Te k t r oni x, I nc . i n one- p oun
d  r ear cast i ng t o t h e si de r ai l s . T h e r ear
cast i ng can now b e
r ol l s ;
or d er by Te k t r oni x P ar t No . 251- 0514- 00
.

r emove d b y p r yi n g i t
of f wi t h ± l ar ge scr ew d r i ver or by