TROUBLESHOOTING THE HMMWV - OD1616 - LESSON 2/TASK 1
(5) Test Number 64.
This test number displays the ID for the
transducer connected to J3 of the VTM.
d.
Offset Tests.
The STE/ICE VTM performs a test by setting the
TEST SELECT switches to the test number and pressing the TEST button.
For some tests, an offset test is required before the test itself can
be performed.
This is done by selecting the number of the desired
test and holding the TEST button down for several seconds.
The offset test nulls out characteristic differences in the VTM, test
leads, and transducers.
It zeros the meter.
Once the offset is
performed, the VTM automatically corrects for the offset before
displaying measured values.
The displayed offset value should be
checked against limits on the vehicle test card.
If the display
value is outside these limits, either the transducer or the test
cable is faulty and must be replaced. This is another form of self-
test.
The offset is performed when each transducer is connected. All tests
requiring offset are identified by an asterisk (*) on the flip cards
and by OFFSET LIMITS on the vehicle test cards. The offset test is
performed with the test probe cable or transducer connected to the
VTM. Care should be taken to see that no stimulus is applied to the
transducer. The test probe cable leads should be shorted together.
To perform an offset test, dial the test number into the TEST SELECT
switches. Press and hold the TEST button until the prompting message
CAL appears on the display.
In a few seconds after the release of
the TEST button, a number will appear. This is the measured offset
value associated with the test probe cable or transducer and cable.
e.
Control Tests. These tests are used to change (or control) the
way a vehicle test is displayed, or the way it is run.
There are
four control tests:
o Test Number 01.
Interleave (displays RPM with next test).
o Test Number 02.
Display minimum value for next test.
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