At this point, you should be able to readily identify most of the
PART C - WIRE TRACING
In addition to being able to "read" the schematic diagram of a
circuit, it is often necessary to trace the source and/or the
destination of a signal coming into the circuit or exiting from it.
This is normally accomplished through a process of wire tracing.
Depending on the design and construction of the equipment, wire
tracing may be simple and confined to the internal parts of the
equipment; or it may be complex and extend to distant external
Wire tracing procedures may vary greatly from one type of equipment
to another. Probably the key to success in wire tracing is to have
an understanding of the reference designators used to identify and
It is important to note that not all
systems use the same methodology for assigning reference designators.
Prior to performing wire tracing on actual equipment, refer to the
appropriate technical manual.
The following reference designator information is applicable
to the tank thermal sight (TTS), AN/VSG-2. The wire tracing
steps refer to the extracts from TM 9-5855-267-24 found in
appendix c. The wire tracing sequences found in this lesson
use table 3-2 of appendix C for solution.
are for training only.
1. Reference Designators. Most equipment that requires the repairer
to trace signals from one unit to another have some type of reference
These reference designators are assigned to
assist the repair technician in locating and identifying components
as necessary for testing and repair.
The TTS, AN/VSG-2 uses the system described below to assign reference
a. The first number in the reference designator represents the
major unit in which the component is located. The major units of the
TTS, AN/VSG-2 are:
(1) Head assembly.
(2) Gunner's display.
(3) Commander's display.