Operating instructions

SECTI.ON 5
MAINTE NA NCE
5.1 Introduction
This section co n tains the necessary
pro ced u res to per form adjus tme nt s and
troub les hoo ti ng of the CE - 7 . If a dj ust -
me n ts ot he r th an th os e de s crib ed a re r e-
qui re d, it is reco m me nde d th at th e in stru-
me nt or suba ss embl y be r eturned to
Cus
hma n Ele ctr oni cs , Custo me r S er vic e
Dep
artm ent for ca li b ra tio n and alignm ent.
It is ass u me d th at the ope r ator is
f amili ar with th e oper atin g p roc e du res
d es crib ed in S ecti on 3. The in stru m ent
sho uld be w ar m ed up fo r at lea st 30 min -
ut
es b ef or e any adj ustme nt or troubl e-
shooting is a tte mp te d . F or mo st of th e
tes ts and int e rn al adjus tme n ts, th e s ide
cove rs and bo tt om cover m ust be r e-
m oved . Th e te st eq u ipme nt req ui re d
f
or each adj ustme nt is give n after pr e-
l imi nar y ins tr uc ti ons (Pa r agr aph s 5 .4 . 1
thr ough 5 .
4. 6). F or ea se of f ollo win g
the ad
jus tm en t p roced ure s o r c heck s ,
the
steps are giv en in ta bula r f orm (Tabl es
5
-2 th ro ugh 5- 7). T r oubl esho oting guid es a ls o
in tabu lar form (Tabl es 5 -8 through 5- 11 )
are p rov ide d to ass is t the ope ra tor in lo-
ca liz ing malfu ncti on s. Int eri or vi ew s of
th e
in strument ar e included to aid in lo-
ca ting the vari ous test and adj ust m ent
points .
5.2 Access
Comp
onents in th e top pa r t of th e in stru-
me nt can be r e ached by r e mo ving th e two
L
-s haped side covers . Eac h cov er is se -
cu
re d to the c hass is by six sc rews . Th e
speake r le a ds m ust be di sco nnec ted be fo re
the r ight - ha nd cover ca n be rem ove d com -
ple
te ly . Co mpo ne n ts in th e b otto m pa r t of .
the i nstr ume nt can be reac hed by setti ng
the CE
-7 . on its r ear pane l, wit h the b ott om
fa
cin g f or ward . Th e bo tt om cover is se -
c
ur ed to the c hass is by six sc rews .
Th e
Model 302 F M D evi ati on M et er
or the Model 301 Osc illo s co pe is r emov ed
by lo
os ening a sm all kn ob on th e r e ar pane l
5601"0015"1
of th e C
E-7 and pus h ing in on thi s knob.
Th e Mo de l 303 Br oadband Mixe r and -Mo del s
304 , 305, or 306 B Pres el ect or ar e r e- .
moved by lo os ening the LOCK knob on the
fr ont pa ne l of the plug -ins, and pus hing in
on
th e knob to d is engage th e plug- in con -
n
ecto r fr om th e CE- 7 recep ta cle .
5.3 Fuses
Th ere ar e thr ee r e gula ted pow er s up-
pli es within th e CE-7: +5 v olt s, +20 volt s,
and
-12 v olts. The +5- vo lt supply is d eriv ed
by m e
an s of a zener cliode f rom th e +20- volt
s upply and doe s, th e r
ef or e n ot hav e a sep-
ara te adjus t me nt or fus e. Se pa rate fu se s
and adj
us t me nts f or the -1 2- and +20 -vo lt
s up p
lie s a re on Po we r Sup ply bo ard 0100
loc
at ed on the rig ht side of t he in s tru-
me nt. See Fig ure 5 -1 . Th e - 12- and
+20- vo lt sup pli e s a re p rotec ted by 1. 0 amp
slo - blo fus e s . The uppe r -adjust ing pote nti -
o
mete r a nd uppe r fus e a re f or th e +20- vo lt
s upply .
The low er- ad justin g pot entio mete r
and
lowe r fuse are f or the -12- vol t supply .
If on e of th e s e f uses blows, th e r e si st anc e
b
et we en the r e gulat or ou tp ut t ermin al and
gro und sh ould be me a sur ed to make s ure
th at th er e is n ot a s ho r t c irc ui t. Tab le 5- 1
gi
ve s the app rox i ma te re s is ta nc es to c hass is
gr ound f or ea ch s uppl y (o r, in the case of
the plu g-in s, f or th e load a cros s ea ch supply) .
Th
er e ar e two s epa r ate AC fus es l o-
cate d on the rea r pa nel of the CE -7 . A
1. 0 a mp s lo- blo fuse is f or th e ma in
AC
powe r to the inst rum ent. The othe r
is a 0 .2 amp slo-blo fus e t hat prov i des
pr o tec tion to the Mo de I 301 Os cill oscope,
wh
ic h ha s a regul a te d power s uppl y.
5. 4 Adju stm ent Pro c edur es and Ch eck
Th e foll owing pa r agrap hs (5.4. 1
th
ro ugh 5 .4 .6) i nter spe rs ed with the ir
re spect i ve ta b les pr ovid e p re limi nary
in structi ons and t es t equipm ent requir ed
for performan ce of th e te st s given to
maintain the C E-7.
5- 1