TROUBLESHOOTING THE HMMWV - OD1616 - LESSON 2/TASK 1
The use of the VTM through the DCA and TK is referred to as the
combined mode.
Additional tests can be done that involve manually
probing and/or connecting transducers to appropriate test points.
Operating power for the VTM is drawn from the vehicle batteries or
some equivalent battery source.
Power is routed to the VTM through
the DCA connected to the battery.
The STE/ICE general purpose
testing capabilities that may be applied to the vehicle are: 0-1000
psig pressure, 0-45 volts dc, and 0-40K Ohms resistance.
The
following control functions can be performed in conjunction with the
special tests: interleave (displays rpm with the next test), display
maximum value, and display minimum value, and display peak-to-peak
value.
(2) Controls and Indicators. The controls and readout display on
the VTM are illustrated in figure 9 (on the following page).
The
following paragraphs will describe how the controls are used and how
the display functions.
(a) Power Switch (PUSH ON/PULL OFF). The power switch controls
dc power to the VTM. The VTM can operate from a 12 Volt or 24 Volt
battery system.
When the power switch is pushed in (PUSH ON), the
VTM power is on.
To shut the VTM off, pull the power switch out.
The power switch will pop out automatically if something is wrong
which causes the VTM to use more power than it should. If the switch
pops out, check the hookup carefully and try again before returning
the VTM to intermediate support (IDS/IGS) maintenance.
(b) TEST SELECT Switches. The TEST SELECT switches are used to
select the actual test to be performed. There are ten positions on
each switch numbered 0 through 9.
The number dialed into these
switches is read by the VTM when you press the TEST button. Changing
the TEST SELECT switch positions has no effect until the TEST button
is pushed.
(c) TEST Button.
Depressing and releasing the TEST button
causes the test measurement to begin. Observe the measured value on
the readout display. The reading will be in units normally used for
the particular vehicle measurement.
These units are listed on the
flip cards.
The TEST button must be pressed and immediately
released.
Depressing and holding the TEST button down initiates an
offset test. Offset tests are described in TM 9-4910-571-12&P.
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