Tektronix 576 - Page 77

Removal of C R T
1 . R emove t he bezel f r
om
t he Ty p e 576
fro
n
t panel .
3 . Disconnect
t h e co nn ector on t h e r ear of t he CRT by
p ulling on t h e w h ite h
an d
le .
CRT .
2 . R emove t h e p ower cor
d
retai n er from t h
e rear p anel .
4 . Disconnect t he p i n conn ectors f r om t he si d e of t he
5 . L oose n t he CR T clamp by loose n i ng t he two
screws
on t he to p rear of t he s h iel d .
6 . Pus h t he CRT from t h e rear, w h ile p ulling it
from t he
front .
R emoval of t he CR T Sh iel d
1 . Remove t he CRT .
2 . Discon nect t h
e s h iel d from t he rear b y loosening t he
screw w h ic h
clam p s t he s h iel d to t h e rear p anel .
3 .
Disconnect t he p in connectors from t he graticule
lig h t
circuit boar d .
4 .
Remove t
h
e two screws securi ng t he s h iel d to t he
f r ont panel .
5 . Pull t he s h iel d o u t from
t he front .
To re p lace t he CRT
and s h iel d reverse t h ese p roce d u r es .
Gua rd Box . T h e guar
d box may be r emove d by t he fol-
lowing proce d u re :
1 . R emove t he b ottom p
anel from
t
he instrument .
2 .
Remove t
he
screws from t he bottom of t he ch assis
w
h ic h h ol
d
s
t h
e
guar d box in place .
3 . Disconnect t h e MAX PEAK V
O
L
TS and t he PEAK
P O WER W ATTS
switc
h
es from
t
h e fro n t p an el .
4 . Disconnect
connector J 300 from t he guar d box .
5 .
Pull
t he
guar d b ox out from the bottom of t h e instr u -
ment .
To
re p lace
t he guar d box, p erform t h is p r ocedure
in re-
verse .
Ci r
cuit Boar d . Replacement .

M ost of t he com p onents
mounte d on t he circuit boards can be re p lace d wit h out
removing t he boards from the i n strume n t . Observe t h e
sol d eri n g p recautions given und er Sol d ering Tec hn i q ues i n
t h is section . If α circuit boar d is damaged beyon d re p air,
eit
h
er t he entire assembly (inclu d i ng all soldered-on-
components) or t he boar d only can be re p lace d . Part num-
M ai n te na n ce-Ty p e 576
bers are given in t he M ec h anical Parts L ist for eit h
er
t h e
com p letely wire d or t he unwired boa r d .
U se t he following p r ocedu re to remove
α circuit b oar d .
1 α . To lift t he boar d for maintenan ce
or access to areas
ben eat h t he board , d isco n nect t h e p in
conn ectors w h ic h
mig h t im p air lifting .
1 b . To com p letely remove t h e
boar d d iscon n ect all t he
remaining p in connecto rs .
2 . R emove all screws h ol d i n g t he boar d to
t
he
c h assis .
3 . L ift t h e circuit board p artially or
all
t h e
way out of
t h
e
inst ru me n t . Do notfo r ce or ben d t he board .
4 . To replace t he boar d , reverse . t h e or d er of removal .
Correct location of the pin connectors is s h own i n F igs . 4-5
throug h 4-26 . Re p lace t he p i n connectors carefully
so t
hey
mate correctly wit h t he p ins . If forced i n to p lace
incorrect-
ly t he p in connectors may be d
amaged
.
Cam Switc h es . Α cam switc h an d its associate d circuit
boar d forms
an
assembly . It is suggeste d t h at maintenance
of α cam switc h w h ic h involves se p arating t he two p arts of
t h e assembly be done only by exp erience
d
tec h
nicia n s .
Removal of α Cam Switch Assembly .
1 α . To remove t he cam switc h assembly for mai n ten-
ance or access to areas beneat h , d isconnect only t hose p i n
connectors w h ic h mig h t imp air lifting .
1 b . To com p letely r emove t he assembly
discon
n ect
all
t he p in connectors .
2 . Disconnect t he switc h from t h e front p a n el .
3 . Discon n ect t he circuit boar d from t he rear mou n ting
brac k et .
ΝΟΤΕ
T h e t h i n film resistors
on
some of t h
e cam switc h
assemblies a r e brittle . Do n ot bend t h
em w hen
h an d li n g .
R e p lacement of α Cam Switc h Assembly .
1 . Connect t
h
e
switc h to t he front p anel .
2 . Connect t he ci r cuit boar d to t he rear mounting
brac k et .
ΝΟΤΕ
Do not
b
e
n
d
th
e circuit boar d w h ile sec u ri ng it to t h e
rear
mou n ting
b
rac k et . If t he circ u it boar d must be
b e n t to secu r e the board to t he rear . mou n ting
brac k et, re-ad j ust t he rea r mou n ti n g brac k et .
3 . R econnect t he pin connections
to t h
e pro
p er p ins
(see F igs . 4-5 t h ro ugh 4-26) .
4-11