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Troubleshooting Aids—221 Service
Ceramic
Capacitors:
Dipped Tantalum
Electroiytics:
(7)
N O T E :
a n d /o r
@
c o lo r co de f o r c a p a c ito rs d epends u p o n
m a n u fa c tu re r and ca p a cito r ty p e . M a y n o t be p resent in som e cases.
Fig. 6-2. Color code for resistors, ceramic capacitors, and dip tantalum electrolytic capacitors.
Component Color Coding
The resistors used in the 221 are either composition
resistors or precision resistors. The resistance values are
color-coded on the components w ith El A color-code (some
precision resistors may have the value printed on the body).
The color-code is read starting w ith the stripe nearest the
end of the resistor. Composition resistors have four stripes
that consist of tw o significant figures, a m ultiplier, and a
tolerance value (see Fig. 6-2). Precision resistors have five
stripes consisting of three significant figures, a m ultiplier,
and a tolerance value.
The capacitance value o f common disc capacitors and
small tubular electroiytics is marked in microfarads on the
side of the component body. The molded electrolytic
capacitors are color-coded in picofarads (see Fig. 6-2)
The cathode end of each glass-encased diode is indicated
by a stripe, a series o f stripes, or a dot.
6-2
Resistor and Capacitor Color Code
Multiplier
Color
Figures
Resistors
Capacitors
___
_______
Silver
i a 3
Gold
—
10"1
—
Black
0
1
Brown
1
10
Red
2
102
Orange
3
103
Yellow
4
104
Green
5
10s
105
Blue
6
10'
106
Violet
7
—
—
8
Gray
—
10"2
White
9
—
10"'
(none)
—
—
—
•For capacitance of 10 pF or less.
•For dipped tantalum capacitors only.
^ 1) ^ 2) a nd
®
—m u ltip lie r; ( j f ) —to le ra n c e :
^
—te m p e ra tu re c o e ffic ie n t:
( ? ) —p o la r ity and vo ltag e ra tin g .
Isolating Trouble To A Circuit
To isolate the trouble to a particular circuit, note the
trouble symptom. The symptom often identifies the circuit
in which the trouble is located. For example, no intensity
indicates that the crt circuit is probably at fault. When
trouble symptoms appear
voltage and waveform measurments. Typical voltages and
waveforms are shown on the schematics in the diagram
section o f this manual
locating a defective circuit.
Start from the top o f the chart and perform the given
checks on the left side o f the page. When a check is
performed that does not produce the indicated results,
further checks and/or circuits in which the trouble is
probably located are listed to the right of this step. After
the defective circuit has been located, proceed to locate the
defective component(s).
Tolerance
Voltage
Capacitors
Resistors
Rating**
±10%
±5%
—
—
±20% or
1
4 VDC
—
2 pF*
± 1% or
10
±1%
6 VDC
0.1 pF*
10"
±2%
±2%
10 VDC
103
±3%
±3%
15 VDC
+ 100%
104
±4%
20 VDC
-9 %
±5% or
±0.5%
25 VDC
0.5 pF*
—
—
35 VDC
50 VDC
—
—
+80%
—
-2 0 %
—
or 0.25 pF*
±10% or
—
3 VDC
1 pF*
± 10% or
±20%
—
1 pF*
—1st, 2 n d , and 3 rd s ig n ific a n t fig ures:
check the circuit by taking
Figure 6-3 provides a guide for
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