Tektronix 454A - Page 112

M ai nt enance- 454zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA ‘ / R 454 ‘
3 . Pul l t he ol d r ee d - r el ay out of t he d r i ve- coi l .

H i gh Vol t age Com p ar t ment . T he component s l ocat e d i n
t he h
i gh- vol t age compar t ment can be r eached f or mai nt en-
ance or r e p l acement by usi ng t he f ol l owi ng p r oce d ur e .
REPLACEMENT :
1 . Sl i p t he new r ee d - r el ay i nt o t he d r i ve- coi l .
2 .
P
osi t i on t he new r eed- r el ay i n exact l y
t he same physi -
cal p osi t i on as t he ol d one .
3 . P osi t i on t he l eads cor r ect l y an d sol der t he new r ee d -
r el ay t o t he sol d er p ost s . Avoi d excessi ve h eat on t he r ee d -
r el ay ; use ± heat si nk on t he l ea d s i f sol d er i ng cl ose t o t he
gl ass bo d y .
4 . Cl i p of f t he excess l ead l engt h beyond t he sol d er
post s . Do not cl i p t he l ea d cl oser t han 1/ 4 i nch f r om t he
gl ass b o d y .
R ot ar y Swi t ches . I n d i vi d ual waf er s or mechani cal p ar t s
of r ot ar y swi t ches ar e nor mal l y not r e p l aceabl e . I f ± swi t ch
i s d ef ect i ve, r e p l ace t he ent i r e assembl y . R e p l acement
swi t ches can b e or d er e d ei t her wi r ed or unwi r ed ; r ef er t o
t he E l ect r i cal P ar t s L i st f or t he a pp l i cabl e par t number s .
1 . R emove t he
b
ot t om
cover of t he i nst r ument as
d
escr i be
d i n t hi s sect i on .
2 . R emove t he h i gh- vol t age shi el d by
l ooseni ng t he t hr ee
scr ews secur i ng i t .
3 .
R emove t he t wo scr ews whi ch hol d t he p l ast i c cover
on
t he h i gh- vol t age com p ar t ment and r emove t he cover .
4 . To r emove t he com p
l et e wi r i ng assembl y f r om t he
h i gh- vol t age com p
ar t ment , r emove t he t wo scr ews whi ch 9 ¿
t hr ough t he t r ansf or mer . Be car ef ul not t o l ose t he h eat -
si nk bl ock beneat h t he hi gh- vol t age t r ansf or mer . Al so
r emove t he pl ast i c scr ew on t he ot her en d of t he h i gh-
vol t age com p ar t ment . Now, u nsol der t he post -
d ef l ect i on
anode l ea d ( heavi l y i nsul at e
d
l ea
d at t he si d e of t he com-
p ar t ment ) . The
ot her l ea d s ar e l ong enough t o al l ow t he
assembl y
t o be l i f t e
d out
of
t he com p ar t ment t o r each t he
p ar t s
on
t he u nder si d e .
When r e p l aci ng ± swi t ch, t ag t he l ea d s an d swi t ch t er -

5 . To r epl ace t he
hi gh- vol t age com p ar t ment , r ever se t he
mi nal s wi t h cor r espon d i ng i d ent i f i cat i on t ags as t he l ea d s

or d er of
r emoval
.
ar e di sconnect ed . Then, use t he ol d swi t ch as ± gui d e f or
i nst al l i ng t he new one . An al t er nat e met hod i s t o dr aw ±
s ket ch of t he swi t ch l ayout an d r ecor d t he wi r e col or at

NOTE
each t er mi nal . When sol der i ng t o t he new swi t ch, be car ef ul
t hat t he sol d er does not f l ow beyon d t he r i vet s of t he

‘ / / sol der j oi nt s i n t h e
h i g h - vol t age compar t ment
swi t ch t er mi nal s . S p r i ng t ensi on of t he swi t ch cont act can

sh oul d h ave
smoot h sur f aces . Any pr ot r usi ons may
b
e
d
est r oye
d b y
excessi ve sol
d
er .

cause hi gh- vol t age
ar ci ng at h i g h al t i t udes .
T he swi ng- out chassi s on t he r i ght si de of t he i nst r ument
p r ovi d es access t o t he si de of t he ¤™œ• / DI V an d HORI Z
DI SPLAY swi t ches . The t op and bot t om of t hese swi t ches
can b
e
r eache d f or
easi er r e p
ai r
or r emoval
by
r emovi ng t he
’ Swee p boar d ( t o p ) or t he ‘ Swee p boar d ( bot t om) .
P ower
Chassi s
. The
power t r ansi st or s and ot her heat
d i ssi p at i ng power - su pp
l y com p onent s ar e mount e d bel ow
t he Low- Vol t age R egul at or b oar d . R emove t he Low-
Vol t age R egul at or b oar d t o r each t hese component s . To
r each t he und er si d e of t he chassi s, r emove
t he f an t hr ough
t he r ear subpanel .
P ower Tr ansf or mer R e p l acement . I f t he power t r ans-
f or mer becomes d ef ect i ve, cont act your l ocal Tekt r oni x
Fi el d Of f i ce or r e p r esent at i ve f or ± r e p l acement ( see t he

Recal
¯ br at ¯ on Af t er Repai r
W ar r ant y not e i n t he
f r ont
of t hi s
manual ) .
B
e sur e
t o
r e p l ace
onl y
wi t h ± di r ect r epl acement Tekt r oni x t r ans-

Af t er
any
el ect r i cal component has been
r epl ace d , t he
f or mer .

cal i br at i on of t hat p ar t i cul ar ci r cui t shoul
d be checked, as
wel l as t he cal i br at i on of ot her
cl osel y r el at e d ci r cui t s .
Si nce t he l ow- vol t age su p pl y
af f ect s
al l
ci r cui t s, cal i br at i on
When
r emovi ng
t he
t r ansf or mer , t ag
t he
l ea d s
wi t h t
he

of t he ent i r e i nst r ument
shoul d be checked i f wor k has
cor r es p on d i ng t er mi nal number s t o ai d i n connect i ng t he

b een done i n t he
l ow- vol t age su pp l y or i f t he power t r ans-
new t r ansf or mer . Af t er t he t r ansf or mer i s r e p l ace d , check

f or mer has b een r e p l aced . The P er f or mance
Check Pr o-
t he p er f or mance of t he com p l et e i nst r ument usi ng t he P er -

ce d ur e i n Sect i on 5 pr ovi d es ± qui ck
an d conveni ent means
f or mance Check Pr oce d ur e .

of checki ng i nst r ument op er at i on .
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