incorrectly. To troubleshoot efficiently, you must
1. symptom recognition,
perform the following five logical operations:
2. malfunction location, and
1. Identify the symptom.
3. repair.
2. Identify the malfunction.
E a c h of these operations is discussed in the
following sections.
3. Localize the malfunction.
4. Locate the cause of the malfunction.
SYMPTOM RECOGNITION
5. Perform failure analysis.
Symptom recognition is the weakest link of the
Identifying the Symptom
three basic operations. Many incidents occur where
malfunctioning equipment is operated for hours, days,
After an equipment trouble is noted, a good
and even months without notice of a failure. The
technician then uses all available aids designed into the
symptoms of many malfunctions are subtle and may not
equipment to further elaborate on the symptom. By
be easily recognized. So, the need for trained operators
using the front panel controls, indicators, and other
and technicians in the methods of symptom recognition
testing aids, you can obtain a better description of the
is very important. To be a good technician, you must first
symptom.
know proper equipment operation and the function of
each operating control.
Identifying the Malfunction
Very often, a qualified console operator can see a
malfunction in the equipment that he or she can correct
Your next step in troubleshooting is to prepare some
without the aid of a technician. A console operator can
logical choices for the basic cause of the symptom. The
make some adjustments to the equipment, provided they
logical choices should be mental decisions based on
do not require a lot of technical skill. Console operators
your knowledge of equipment operation and a full
are not always technically qualified technicians to work
description of the symptom. The overall function
on the consoles they operate. They are, however, still
description in the technical manual can help you outline
responsible for reporting any symptoms of malfunction
the logical choices.
to a GSE.
Localizing the Malfunction
Not all equipment produces symptoms that are
easily recognized. Some symptoms can only be found
Now that you have identified the malfunction, you
while preventive maintenance is being performed. For
m u s t localize its basic source. L o c a l i z i n g the
these reasons, you must recognize the not so apparent
malfunction is normally accomplished by using the
as well as the apparent troubles.
block diagrams in the technical manuals. You can test
the logical choices by following the signal flow of the
MALFUNCTION LOCATION
faulty function. If one test does not prove that the
function is faulty, test the next logical choice. Continue
The process of malfunction location is better known
this procedure until you can localize the faulty function.
to the GSE as troubleshooting. This process begins after
a symptom of a malfunction has been recognized and
Locating the Cause of Malfunction
ends when the cause of the malfunction is located.
GSEs, operators, and others who have worked with
After localizing the malfunction, you must make
electronic equipment know what troubleshooting is.
additional choices to find which circuit is at fault. Again,
But, then, why does so much downtime occur?
use the block diagrams (with schematics) to find the
Modern electrical and electronic equipment is
faulty circuit. If the trouble is not immediately apparent,
extremely complex because of so much interfacing and
use proper test methods to further isolate the fault. Some
interacting circuitry. To troubleshoot this type of
common test methods you may use include voltage and
equipment can be annoying. Your troubleshooting
resistance checks, semiconductor testing, and module
efficiency depends on the knowledge that you have of
testing. Continue this process until you locate the
the operation of the equipment. This is very important.
specific cause. Defective components, improper wiring,
You must first know what the equipment does before
and improperly soldered components are all examples
you can determine what it is not doing or is doing
of specific causes.
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