obviously not in proper condition, correct these
Q7. When removing a victim from electrical
faults before going any further. The types of
contact, you should not take what action?
things to look for include open circuit breakers,
improperly placed switches, burnt equipment,
loose mountings, disconnected components, and
dented equipment.
Q8. List the three classes of fires.
If you can't find anything after visually
inspecting the equipment, check the condition of
fuses and circuit breakers. Sometimes, a circuit
protector will open. If so, reset or replace the
Q9. What is the preferred fire extinguishing
circuit protector and apply power. If the protector
agent for electrical fires?
opens again, secure the power because there is a
probable circuit malfunction. Don't apply power
until after you correct the malfunction.
At this point, use the MIM for equipment. By
Q10. What are the two basic rules you should
using the MIM, you will know which pin in a
follow when working with hand tools?
connector is the power input to the connector.
You can use the MIM to close the correct circuit
breakers and locate the switches to use for testing.
If there is power to the component and it still does
TROUBLESHOOTING TECHNIQUES
not work, then the fault is with the component
itself.
Learning
Objective: Recognize trouble-
If a short, ground, or overload condition is
shooting
techniques, including how to
not indicated, take power readings at the
analyze,
detect, and correct faults in
checkpoints shown in the MIMs. Common faults
electrical
equipment.
that interrupt power through a circuit are broken
wiring, loose terminal or plug connections, faulty
You will spend most of your time trouble-
relays, and faulty switches. Look for these
shooting the equipment in squadron aircraft. You
conditions when checking points along a circuit.
maintain many components and systems that are
If there is no power reaching the component,
complex and difficult to troubleshoot. However,
assume that the component is good, and start
the most difficult troubleshooting job will become
checking the power supply. Begin the check at the
simple if you break it down into the following
bus that supplies the power. If you find evidence
steps:
of a short circuit or overload, secure the power.
At this time, you need to make continuity and
1. Analyze the symptom.
resistance checks.
2. Detect and isolate the trouble.
3. Correct the trouble and test the work.
Continuity and Resistance Checks
ANALYZE
The process of fault detection often leads
If you don't understand a system or com-
beyond visual inspection and power checks. You
use a voltmeter to find out if a power circuit is
ponent, you can't find out what's wrong with it.
delivering power to the proper place. However,
The following are tools that will help you analyze
the voltmeter won't identify what is wrong. An
what's wrong with a system or component:
ohmmeter is a better instrument for identifying
the problem. With the ohmmeter, you can find
Maintenance instructions manuals (MIMs)
opens, shorts, grounds, or incorrect resistance
values. You use the schematic to trace circuits in
Schematics
components, part by part and wire by wire, until
you isolate the trouble. You can use the MIM for
Records on the equipment
the equipment to find the proper resistance
DETECT AND ISOLATE
readings.
At intermediate maintenance activities,
bench-test installations are used for off-equipment
The first thing to do when troubleshooting is
testing. In this type of installation, there is a
to visually inspect the component. If parts are
