Tektronix 576 - Page 68

M
ai
n
te
n ance-Ty p e 576
th e o p eration of th e Ty p e 576 circuit r y is also h el p ful for
locating tro u bles . See t he Circuit Descri p tion section for
com p lete information .
Troubles
h
ooting Aid s
Diag r ams . Α com p lete set of circuit d iagrams is given on
foldout pages in Section 8 . T h e circ u it number and electri-
cal value of eac h com p onent in t h is instrument is s h own on
t he app ropriate
d
iagram
.
Each
main circuit is assig n ed α
series of circuit
numbers . Table 4-1 lists t he main circuits in
t he Ty p
e
576
a nd
t
he
series of circuit
n umbers assigned to
eac h . T he p ortio n s of
t
he circuit w
h
ic h
are
mo u nted on α
circ
u
it boar d are en close d wit h α blue
li ne
on
t h
e
circuit
d iag r am .
TA BLE 4-1
Com p onents Numbers
Also included on t he circuit d iagrams are voltages and
waveforms w h ic h ca n be expecte d at va r ious p oints i n t he
circuitry .
Α list
of fro n t-panel control settings w h ic h must
be used to obtain
t h
e
given voltages and waveforms is
s h ow n on t he apro n of circ u it diagram number one .
Switc h W afer I d entification . Switc h wafers s h ow n on
t he
d
iag r ams are cod
ed
to i nd icate t he p osition of each
wafer in t h e com
p
lete switc
h assembly . T he n umbe r ed p or-
tion of t he co d
e
refers to t h e wafer
number
counting
from
t h e front, or mounting en d of t h e switch , towar d t he rear .
T he letters F an d R in d icate w h et h er t h e front o r rear of
t h e wafer performs t h e p articular switch ing functio n . F or
exam p le, α wafer desig n ate d by 2 R in d icates t
h
at t h
e
rear
of t he second wafer(from t he front) is use d for t h is p
arti-
cular switch i n g function .
Circuit Board s . F igs . 4-5 t h roug h 4-26 sh ow t he circuit
boa r d s use d in t he Ty pe 576 . On each of t h ese p ictures
each electrical com p onent on t he boar d is i d en tifie d by its
ci r cuit number . T h ese p ictures, used along wit h t h e circuit
diagrams, ai d in locating t he com p onents mounte d on t h e
circuit board s .
4- 2
Wi r ing Color Co de . All insulated wire and cable use d i n
t he Type 576 is color-code d to facilitate circuit tracing .
Signal carryi n g lea d s have w h ite bac k grounds with one or
two colore d st r i p es . T he signal ca r rying wire color-co d es are
given in F ig . 4-5 t h roug h 4-26 with t he approp riate p in
connection . P ower su pp ly lea ds have eit h er α re d bac k -
groun d ( p ositive su pp ly) or α pur p le bac k ground (negative
su pp ly) .
E
ac h p ower supp ly lea d also
h
as on
e
colored stri p e
w h ic
h re p
resents its o
r
d inal relations h i p to t
h
e oth
er
supp
lies h
avi n g
t
h e
same
p
olarity, using t h
e
ΕΙΑ resistor
color co d
e .
Table 4-2 gives t he wiring color-cod
e
for t
h
e
power su pp ly voltages used in t
h
e Ty pe 576 .
Table
42
P owe r Supp ly Wiring Color
R esistor Colo
r
Co d
e . In add ition
to
t he brown com p osi-
tion resistors, some metal-film
resistors
(i d entifiable
by
t h eir gray bo d y color) and some wire-wo und resistors
(usually lig h t blue or d ar k gray) are used i n t he Ty pe 576 .
T h e resistance value of α wire-wound resistor is p rinte d on
t h e bo dy of t he com p onent . Th e resistance value of α com-
p osition resistor or metal-film resisto r is color-co d e d on t he
com p
o
nent with ΕΙΑ color-code (some metal-film resistors
may
h
ave t
h e
value p rinte
don t h
e
bo d y) .
T
he color-code is
rea d starting wit
h
t he stri pe nearest t he en d of t he resistor .
Com p osition resistors have fo
u r
stri
p
es w h ic h consist
of
two significant
figures,
α
multi
p
lier
and α tolerance value
(see F ig . 4-1) . M etal-film resistors
h
ave five stri pes con-
sisting of t h ree
significant
figures, α multi p lier an
d
α
toler-
ance value .
Ca p
acitor M ark
ing .
T
h e capacitance
val u
e of α common
d isc ca p acitor or small electrolytic is mar k e d i n microfara d s
on t he side of t he com p onent body . T he w h ite ceramic
cap acitors used in t h
e
Ty p
e
576 are color-cod
e
d in p ico-
fara d s using α mo d ifie d ΕΙΑ code (see F ig . 4-1) .
Diode Color Code . T he cath ode en d of each glass
encased diode is indicated by α stri p e, α series of stri p es or α
d ot
.
F or most
silicon or germanium
diodes with α se r ies of
stri p es, t he color-co d e i d entifies t h e Te ktronix P art N umbe r
using t h e resistor color-code system (e .g ., α d io de color-
Su pp ly B ackgro un d
Colo r
Stri pe
Color
-75 volt P urp le Re d
-12 .5 volt P ur p le B lac k
V ar +4 .5 volt Brown (none)
+5 volt Re d B lac k
+12 .5 volt Re d Brown
+50 volt
Re d Yellow
+15 volt Re d Ora nge
+100 volt Re d Green
+225
volt Re d B lue
-4
kV
Wh ite Purp le
Ground Black
(none)
Com p one n t
Numbers
on Diagrams
Diagram
N
umbe
r Circuit
1-99
2,4 Step Generator
100-199 3,4 Step Amplifier
200-299 3,4 Step Am p lifier
300-399 1,6 Collector S u pp ly, Standar d
Test F ixture
400-499 5,8 Display Sensitivity Switc h i n g,
Dis p lay P ositioning
500-599 9 V ertical Display Am
p
lifier
600-699 9 H orizontal
Disp
lay
Am p lifier
700-799
13 P
owe r Su
pply
800-899
14
C
RT Circuit
900-999 10,11 Rea d
out Switc h ing and
Ι n terconnectio n s,
Rea d out L ogic
1000-1199 12 Reado
u t
L am
ps