Tektronix 576 - Page 72

M ainte n ance-Ty pe 576
(
Co nn ect Ty p
e 576 to co r rect
Α )
Ι p owe r source and
set P O WER
switc h to ON .
C h ec
k power supp ly
test
p oi n ts as desc r i b ed
i n ste p 1
a
nd 2 of Sectio n 5,
P e rfo rm .
a n ce C h eck a nd
Cali b ratio n
Pr oced u re .
Cor rect
P O WER
lig h t
on
Attac
h oscillosco p e Χ 10 p r ob
e
to rig h
t collector ter mi n al
of
Sta
nd a rd Test F ixt ure a
n d
(
Β
)
c h ec k
for p ositive-goi ng full
wave r
ectifie d sine wave of 15
V p ea k
.
Co rr
ect
Attac h
oscilloscope Χ 10 pr o be
to r
ig h t base ter mi n al of
Sta nd -
ar d Test
Fixtu re an d c h ec k fo r
10 p
ositive-going steps at
2
V /step .
Pr ess zer o
butto n and p ositio n
s pot on zero vertical an
d h ori-
zo n tal g r atic u le li n es .
Sp ot
positio n e d
pr ope r ly
Press CA L bu tton a nd c
h
ec
k
for s p ot
on te n th vertical a
nd
ho
r izontal li n es .
Ι nco rr ect
Νο or i n co
rr ect Ste p
Ge
n er ato r out p ut
Νο
or i n cor rect Collecto
r
Supply
ou t p ut
P O WER
lig h t does
n ot come on
M easu
r e p owe r line voltage
a
nd c heck t h at V oltage
Selec-
to r assem b ly on rea
r p anel is
set to cor rect voltage .
C h ec k
Collecto r
S up p ly circ u
it .
Attac h oscillosco
p e
Χ 10 pro be
to
pin
ΑΙ of Ste p
Ge n ci r -
cuit b oar
d a n d
ch ec k
for 10 n ega-
tive-goi
ng ste ps of
0 .5
V /ste p .
Yes
S pot ca
nn ot be co rr ectly posi-
tioned
vertically .
Spot can not be co rr ectly
p osi-
tione dho rizon tally .
Νο s p ot
S p ot positio n
i n co rr ect vertically
Spot
p ositio n
i n co rr ect h orizo n tally
Spot p ositio n i
n co rr ect bot h ve r-
tically a nd ho r
izo n tally
S p ot p
osition cor rect
Νο
Yes
Νο ste p s
o r steps
C h ec k fuses, powe r
switc h ,
p owe r sour
ce, p owe r t ran s-
for me r , powe
r lig h t bu lb, t h er-
mal
cuto ut a nd li n e cor d .
Co
rr
ect Ι
Set assem b
ly
to
cor-
rect voltage a
nd r e-
ch ec
k affecte dp ower
su pp
lies .
C h eck H orizo n
tal
A
mp lifie r circ u it .
Still i n
cor r ect
C heck
P owe r
s up p ly ci r cu its .
Ch ec k
Cloc k ci r cuit
I ncorrect
nu m be r
or am p litu de
C h ec k Digital-to-
A n alog Co nverter cir-
cuit .
C h ec k O utput Ste p
A mp lifier ci rcu it
.
C heck V e r tical P ositio n ing
and Display Am p
lifie r ci r -
cu its .
Ch ec
k H o rizo n tal P ositio n -
i ng
a nd Dis p lay A mp lifier
circ u its
.
Ch ec k bot h Dis p lay
Ampli-
fiers a nd P ositio n i n g
cir-
cuits .
C h eck V ertical
Dis p lay Am-
plifie r circuit .
Dis p lay
C
heck b oth Dis p lay Am p li-
fier ci
r c u its .
If zer o a nd cali br ation
r efer -
e
nce s p ots a re co rr ect bu
t
t he d
is p
lay
of c ha racte r istic
c u
rves is still i n cor r ect,
ch ec
k t he Dis p lay Se n
sitiv
ity
Switc h i ng ci rcu it .
4- 6
Fig . 4-3 . Tr o ub l es h ooting c
h art .