Section 2. Troubleshooting Procedures
1. General
Troubleshooting is an orderly process of checking and eliminating possible causes of trouble until the
exact cause of a trouble is found. As a rule, the best place to start looking for the cause of a trouble in a
circuit is at the source of power. Continue testing and checking the circuit, step-by-step, in an orderly
manner, until the cause of trouble is located. See connection and schematic diagrams.
2. Troubleshooting Chart
a. Description
The troubleshooting chart lists information under three headings:
(1)
Trouble, symptom, and condition,
(2)
Probable cause
(3)
Test, check and remedy
b. Use of the Troubleshooting Chart
Read the trouble symptoms and conditions before proceeding to causes and remedies. For example,
at the beginning of the troubleshooting chart under ENGINE, the first trouble listed is: “Engine will not
start. Starter will NOT crank engine.” If the starter WILL crank the engine, then obviously this is not
your symptom and condition. Go the next trouble and symptom directly below. If the starter will NOT
crank the engine, look to the right under PROBABLE CAUSE and TEST, CHECK, AND REMEDY
and find the various things which could cause the trouble and what to do to check and remedy them.
3. Equipment for Troubleshooting
A good quality, multi-scale voltmeter is the only instrument required similar clips, will be required. The 12
volt engine electrical system may be used for a 12 volt DC power source.
Loose garments, neckties, and other hanging items must not be worn by
personnel near the fan or other exposed moving parts of this equipment while it
is running. Also, avoid contact with live electrical parts. Death or serious injury
could result!
4. Diagrams
For each of the the generator sets covered by this manual an electrical schematic and connection
diagram is provided in the Manufacturers Literature chapter of this manual. These diagrams can be
very helpful in troubleshooting. Components shown in the diagram are identified by reference
designators
(or item names in some instances)
. A legend appearing on the diagram identifies each
reference designator by its full item name. For example, the symbol K403 identifies the overvoltage
relay, and M406 identifies the voltmeter.
5. Illustrations
To aid maintenance personnel with troubleshooting, three illustrations are provided in this section,
showing the locations of various components of the generator set.
6. Connections and Wiring
Before condemning any electrical component, check all connections and wiring which could affect its
operation. In many instances a component may be non-functional simply because it is not receiving
power because of a loose connection or a poor ground. In most cases throughout the troubleshooting
chart, it will be assumed that connections and wiring have been checked.
WARNING
OM-2063 / Operation and Maintenance Manual
Jet-Ex 4D / Spec. 7003A-3 / Generator Sets
Dec 31/92
Chapter 2-2
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