C1, TM 9-1240-318-35
CHAPTER 4
TROUBLESHOOTING
Section I. GENERAL
4-1. Purpose
troubleshooting to avoid further damage.
Troubleshooting is a systematic isolation and remedy of
4-2. Scope
malfunctions and defective components by means of
symptoms and tests.
Close adherence to the
This chapter covers troubleshooting which is peculiar to
procedures covered herein will materially reduce the
direct support, general support, and depot maintenance
time required to locate trouble and restore the equipment
operations. For troubleshooting procedures performed
to normal operation.
by lower categories of maintenance refer to
TM
9-2320-224-20
for
telescope
M120
and
Caution: Operation of telescope without a
TM 9-2350-300-20 and TM 9-1005-286-20 for telescope
preliminary examination can cause further damage
XM134.
to a faulty component.
Exercise care during
Section II. TROUBLESHOOTING
4-3. General
4-4. Procedure
The troubleshooting procedures describe possible
Table 4-1 describes the troubleshooting procedures.
malfunctions and the necessary corrective actions.
Table 4-1. Troubleshooting
Lowest
Malfunction
Probable cause
Corrective action
maintenance
category
Target blurred or foggy
Dirt or finger prints on optics
Clean with lens tissue moistened
DS
with alcohol.
a. Improperly sealed.
a. Reseal, purge, and charge (para
Depot
optics
b. Defective preformed packing.
DS
Parallax between target
a. Objective cell loose in
a. Remove parallax and secure cell
GS
and reticle
housing.
b. Objective lens loose in cell.
b. Tighten lens in cell and check
GS
Reticle not sharp and clear
Eyepiece not adjusted properly.
Adjust and secure eyepiece (para
GS
Reticle not plumb
a. Reticle loose in cell.
a. Tighten reticle in cell and plumb
GS
b. Reticle cell loose in housing.
GS
4-1