Tektronix 576 - Component Replacement and Repair

M ainte n an ce-Ty pe
576
Sol d
ering Tec h ni q ues
W A RN I NG
Disco
nn ect t he instrument from t he p ower source
before
sol de r ing .
Circuit Boar d s . U se
ordinary 60/40 sol d er and α 35- to
40-watt p e n cil type
solderi n g iron
on
t he circuit boards .
T h e ti p of t he iron s
h
oul d
be clean and p ro p erly tin ned for
best h eat tra n sfer to t he sol d er j
oint . Α h ig he r wattage
sol d ering iro n may se p arate t he
wiri n g from t h e base
material .
T
h e following tec h ni qu es s h oul d be use d to re p lace α
com p onent on α ci r cuit boar d . M ost com p onents can
be
re p
lace
d without removing t he boar d s from t he instrument .
1 . Gri p t he com p o nent lea d wit h long-nose
p liers .
Touc h t he sol d ering iron to t he lead at t he solder connec-
tio n . Do not lay t he iro n di r ectly on t he boa r d , as it may
d amage t he boar d .
2 . Wh en t h e solder begi n s to
melt,
pull
t he lead out
gently . T h is s h ould leave α
clea n h ole i n t h e board . If not,
t he h ole can be
cleaned
by re h eating
t he sol de r and p laci n g
α s h ar p ob j ect s uc h as α toot h p ic k into
t he h ole to clean it
out . Α vacuum-ty p e d esol d
ering tool can also be use d for
t h is p ur
p
ose .
3 . B end t he leads of t h e new com
p onent to fit t he holes
in t he
boar d . If t he com p onent is re p lace d
w h ile t h e boar d
is
mou n te d in t he i n strument, cut t he lea d s so
t hey will ju st
p rotru
de t h ro u gh t he board . I nsert t he lea d s i
n
to
t he h oles
in the
boar d so t he com p onent is firmly seate d
against t h e
boar d (or
as p ositione d originally) . If it does not seat p r o-
p e r ly, h
eat t
he solder
and gently p ress t h e com p one n t into
p lace .
4 . Touc h t he iron to t
he con n ection and apply α small
amount of sol d er to ma k e α firm solder
j oint . To p rotect
h
eat-sensitive com p o n ents, h ol d t he lea d
betwee n t he com-
p onent body and t he sol d
er j oint with α p air of long-nose
p liers or ot h er h eat sin
k .
5 . Clip off t h e excess lea d t
h
at
p rotru d es t h roug h t he
board (if not cli pp ed
in ste p 3) .
6
. Clea n t he area arou nd t he sol d er co
n nection with α
flux-remover solvent . Be careful not to remove
information
p rinte d on t h e boar d .
Ceramic Terminal Stri p s . Sol d er
use d on t he ceramic
te r minal stri p s s h oul d contain about 3°/
ο
silver
.
U se
α 40- to
75-watt sol de r ing i r on with α 1/8-i n c h wid
e we d ge-s h a ped
ti p . O
r d i n a r y sol d er ca n be use d occasionally
with out dam-
age to t h e ceramic termi n al strips .
H owever, if or d inary
sol d er is used re p eatedly or if
excessive h eat is app lie d , t he
sol d er-to-ceramic b ond may be
broken .
4- 1 0
Α sam p le roll of solde r
containing about 3°/ ο silver is
mounted on t he rig h t si de of t h
e
i
n strument below the
brac k et hol d ing t h
e
VER T O UT PU
T
GAI
N
an
d H O R IZ
O U T PU T GAI N a d j ustments . Additional sol d er of
t h e same
ty pe s h oul d be available locally, or it
can
be
p urch ase d
from Te k tronix, I nc . i n
one- p oun d rolls . ord er by Te k -
tro n ix Part Νο . 251-0514-00
.
Observe
t h e followi n g p recautions w h en sol d ering to α
ceramic
terminal stri p :
1 . U se α
h ot iron fo r α s h ort time . Apply only en oug
h
h eat to ma
ke t h e sol d er flow freely .
2 . M
aintain α clean, p ro p erly ti nn ed tip .
3 . Avoid p
utting p ressure on t he ceramic terminal stri p .
4 .
Do
not attem p t to fill t he terminal-stri p notc h with
sol d
er ; use
only
enoug h sol d er to cover t h e wires adequate-
ly .
5 . Clea
n t he flux from t he terminal stri p with α flux-
remover solve
n t .
M
etal
Terminals . Wh en sol d eri ng to metal termi n als
(e .g ., switc h termi n als, p otentiometers, etc .), or d inary
60/40 sol d er ca n be use d . U se α sol d ering iron wit h α 40- to
75-watt rati
n
g
and α 1/8-i nch wide wedge-s hape d ti p .
Observe
t h e following p recautions w he n soldering to α
metal
terminal :
1 . Apply only enoug h h eat to ma k e t h e solder flow
freely .
2 . Apply only
enoug h sol d er to form α solid connection .
E xcess sol d er
may imp air t he function of t he p art .
3 .

If
α wire extend s beyond t he sol d er j oi n t, cli p off t he
excess .
4 . Clean t h e flux from t he sol d
er j
oint
with α flux-
remover solvent .
Com p onent R emoval an d
R ep lacement
WA RN I N G
Discon
nect
t he instrume n t from the p ower source
before r eplaci ng components .
N ot all t h e com p onents
in t h is instrument are accessible
with out first
removing some obstructions, such as circuit
boar d s, CRT an
d sh iel d or t he guar d box . N one of t h ese
obstructions,
h owever, are difficult to remove or re p lace .
C R T
a
nd Sh iel d . To remove t h e C RT or t he C R T and
s
h iel d , follow
t h ese p roce du res :