TM 11-6625-586-45
CHAPTER 2
TROUBLESHOOTING
Section I. GENERAL TROUBLESHOOTING INFORMATION
WARNING
2-2. Organization of Troubleshooting
a. General. The first step in servicing a defec-
When servicing the signal generator be
tive signal generator is to localize the fault. Lo-
extremely careful because of the high
voltages present in the unit. Voltages
calization means tracing the fault to the stage
or circuit responsible for the abnormal operation
as high as 230 volts exist at the power
connections. Death or serious injury can
of the signal generator. The second step is to iso-
late the fault. Isolation means tracing the fault
result from contact with any of these
voltages. Always disconnect the power
to the defective part or parts responsible for the
c o r d when performing maintenance
abnormal conditions. Some defective parts, such
which does not require power. Be ex-
as burned resistors, arcing, and shorted trans-
tremely careful when handling or test-
formers, can often be located by sight, smell, and
ing any part of the signal generator
hearing. Most defective parts, however, must be
isolated by checking voltages and resistances.
with the power turned on.
b. Localization. The signal generator consists
CAUTION
of one physical unit that contains several sub-
Before connecting the signal generator
assemblies. The first step when tracing a trouble
to the ac power source, check the posi-
is to locate the stage or circuit in the sub-assem-
tion of 115V240V switch S3. Set this
bly that is at fault by the following methods:
switch to the 115V or 230V position de-
(1) Visual inspection. Visual inspection will
pending upon the ac power source avail-
locate faults without testing or measuring cir-
able. Operation of the signal generator
cuits. Meter readings or other visual signs should
from a 230-volt ac power source with
be observed, and an attempt made to sectionalize
switch S3 in the 115V position may
the fault to a particular stage.
cause serious damage to the unit.
(2) Operational tests. Operational tests fre-
quently indicate the general location of trouble.
2-1. General Instructions
In many instances, the tests will help in deter-
a. Troubleshooting at general support and de-
mining the exact nature of the fault. The preven-
pot maintenance level includes all the techniques
tive maintenance checks and services chart (TM
outlined for organizational maintenance and any
116625586-12) is a good operational test.
special or additional techniques required to iso-
(3) Troubleshooting chart. The troubleshoot-
late a defective part. The general support and
ing chart (para 25) lists symptoms of common
depot maintenance procedures are not complete
t r o u b l e s and gives (or references) corrective
in themselves but supplement the procedures de-
measures. Such a chart obviously cannot include
scribed in TM 116625586-12. The systematic
all trouble symptoms that may occur. The re-
troubleshooting procedure for general support
pairman should use this chart as a guide in ana-
and depot maintenance begins with the operation-
lyzing symptoms that may not be listed.
al checks that can be performed at the organiza-
c. Isolution. Procedures for isolating troubles
tional level, and is completed by means of localiz-
are given in paragraph 26.
ing and isolating techniques.
d. Techniques. In performing the localization
and isolation procedures, one or more of the tech-
b. The signal generator may be removed from
niques below may be applied. Apply these tech-
its dust cover by removing the four screws at the
niques only as indicated, and observe all cau-
rear of the case and sliding out of the case by
tions.
pulling on the panel-mounted handles.
2-1
