Tektronix 434, Instruction Manual, Page: 70 / 222

Maintenance—434
Circuit Boards. Figs. 8-1 th ro u g h 8-23 in th e D iagram s
s e c tio n show th e c ir c u it boards used in th e 4 3 4 . F ig. 4-5
shows th e lo c a tio n o f each b o a rd w it h in th e in s tru ­
m e n t. Each e le c tric a l c o m p o n e n t o n th e b o a rd s is id e n ti­
fie d b y its c ir c u it n u m b e r. These p ic tu re s , used along
w it h th e d ia g ra m s, aid in lo c a tin g th e c o m p o n e n ts m o u n te d
on th e c ir c u it boards.
Wiring Color-Code. A ll in su la te d w ire and cable used in
th e 4 3 4 is c o lo r-c o d e d to fa c ilita te c ir c u it tra c in g . T a b le 4-1
gives th e w irin g c o lo r-c o d e f o r th e p o w e r-s u p p ly voltages
used in th is in s tru m e n t.
T A B L E 4-1
Power Supply Wiring Color Code
S u p p ly Background
Color
S trip e
— 15 v o lt P urple B la ck
+ 15 v o lt Red B la ck
+ 115 v o lt Red B ro w n
+ 2 5 0 v o lt Red Orange
Resistor Color-Code. In a d d itio n to th e b ro w n c o m ­
p o s itio n re sisto rs, m e ta l-film resistors and som e w ire -w o u n d
resistors are used in th e 4 3 4 . T h e resistance o f a w ire -
w o u n d re s is to r is p rin te d on th e b o d y o f th e c o m p o n e n t.
T h e resistance values o f c o m p o s itio n resistors and m e ta l-
f ilm resistors are c o lo r-c o d e d on th e c o m p o n e n ts w it h E IA
c o lo r-c o d e (som e m e ta l-film resistors m a y have th e value
p rin te d o n th e b o d y ). T h e c o lo r-c o d e is read s ta rtin g w ith
th e s trip e nearest th e end o f th e re sisto r. C o m p o s itio n
resistors have fo u r s trip e s w h ic h c o n s is t o f tw o s ig n ific a n t
fig u re s , a m u ltip lie r and a to le ra n c e value (see F ig . 4 -2 ).
M e ta l-film resistors have fiv e s trip e s c o n s is tin g o f th rt-'
s ig n ific a n t fig u re s , a m u ltip lie r and a to le ra n c e value.
Capacitor Marking.
T h e ca p acitance values o f c o m m o n
disc c a p a c ito rs and sm all e le c tro ly tic s are m a rk e d in m ic ro ­
fa ra d s on th e side o f th e c o m p o n e n t b o d y . T h e w h ite
c e ra m ic c a p a c ito rs used in th e 4 3 4 are c o lo r coded in p ic o ­
fa ra d s using a m o d ifie d E IA code (see Fig. 4 -2 ).
Diode Color-Code.
T h e c a th o d e end o f each glass-
encased d io d e is in d ic a te d b y a s trip e , a series o f strip e s o r a
d o t. F o r m o s t s ilic o n or g e rm a n iu m d io d e s w ith a series o f
s trip e s , th e c o lo r-c o d e id e n tifie s th e th re e s ig n ific a n t d ig its
C o m p o s itio n Resistors:
M e ta l-F ilm Resistors:
C era m ic C a p a cito rs:
Resistor and C apacitor Color Code
O © © — 1st, 2 n d a n d 3 rd s ig n ific a n t fig u n
© — m u ltip lie r; ( J ) — to le ra n c e ;
— te m p e ra tu re c o e ffic ie n t.
C o lo r
S ig n ifi­
cant
Figures
M u ltip lie r Tolerance
Resis­
tors
C a p a c i­
tors
Resis­
tors
C a p a c i­
tors
Silver
. . .
io-= ± 1 0 %
—
G o ld
—
10-*
—
± 5 %
Black 0 1 1 —
± 2 0 % or
2 pF*
Brown 1 10 10
± 1 %
± 1 % or
0.1 pF*
Red 2
10- 102 ± 2 % ± 2 %
O ra n g e 3 1.0*
103 ± 3 % ± 3 %
Y e llo w 4 104
104 ± 4 % + 100%
- 0 %
Green
5
105
105 ± 0 .5 % ± 5 % o r
0.5 pF*
Blue 6 10° 10°
—
V io le t 7
—
. . .
G ra y
8 10--
+ 8 0 %
- 2 0 %
o r 0.25 pF*
W h ite 9
10-1 ± 1 0 % o r
1 pF*
(none)
± 2 0 % ± 1 0 % or
1 pF*
♦ For c a p a c ita n c e o f 10 pF o r less.
NOTE: ( T ) a n d / o r ^ C ) c o lo r code f o r c a p a c ito rs d e p e n d s up o n
m a n u fa c tu re r a n d c a p a c ito r ty p e . M a y n o t be p re s e n t in some cases.
4-3
F ig . 4 -2 . C o lo r - c o d e re s is to rs a n d c e r a m ic c a p a c ito rs .