3. Continuity Checks. Continuity checks can be made between various
points in a circuit using a meter and wiring diagrams.
However,
continuity charts are provided for ease in performing the checks.
These charts use reference designators as a basis for their format.
Appendix C is such a continuity chart for the TTS, AN/VSG-2.
It
consists of table 3-2 and included figures from TM 9-5855-267-24.
NOTE:
All continuity checks are made with a DMM set at 2K ohms.
In appendix C, the circuit points used to conduct continuity checks
are found in the two left hand columns.
These circuit points are
identified by their reference designators.
In this table, the
reference designators are indicated in one of two ways:
a. Refer to page 3-5 of appendix C. At the top of the page, the
statement is made, "prefix all test points 3W4." Only the remainder
of the reference designator is indicated in the circuit point
columns.
b. Refer to page 3-10 of appendix C.
The entire
reference
designator is represented in the circuit point columns.
The center column of table 3-2 of appendix C (signal function or
name) identifies the signal carried on the wire being checked.
The
remaining columns provide information pertaining to the conductor.
4.
Signal Tracing.
Many signals produced in one unit of the
equipment are sent or applied to another unit of the equipment.
Often it is necessary for the repairer to "trace" these signals from
one unit to the other. This is accomplished by wire tracing. Table
3-2 and its accompanying figures may be used to trace various signals
from unit to unit within the TTS, AN/VSG-2 and its test set.
The
following example will demonstrate signal tracing in the TTS,
AN/VSG-2.
NOTE:
All page numbers identified
in
the
wire
tracing
sequences
below refer to appendix C.
The following procedures will be used to trace the WFOV CMD from
circuit point 2W1P4-20 to 1W1XA4-8:
a. The reference designator 2W1P4-20 indicates that this circuit
point is located in the gunner's display. Therefore, you will locate
the circuit point in the gunner's wire harness
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