DC Voltage Measurement.

Maintenance of The M113a1/a2 Personnel Carrier
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setting up the AN/URM-105 multimeter for dc voltage measurement is mechanically

zeroing the multimeter.

The selector switch must then be turned to the dc volts

range required for the voltage being measured (figure 13 on page 36). As with the

other two multimeters, if the voltage to be measured is not known, begin with the

selector switch in the dc VOLTS 1000 position. Then, if the first reading was less

than 100 volts, set the selector on dc VOLTS 100. If the second reading was less

than 10 volts, set the selector at dc VOLTS 10 and take a third reading.

(d) DC Voltage Measurement.

The method for measuring dc voltage is similar

for all three multimeters.

First, mechanically zero and set up the multimeter.

Remember, if the voltage to be measured is unknown, be sure to start with the

highest range available on the meter being used to avoid damage to the multimeter.

Connect the red probe to the positive (+) side of the circuit being tested and the

black probe to the negative (-) side. If the needle tries to move off scale to the

left, reverse the probes on the circuit under test. On the Simpson 160, read the

dc scale for the range chosen by the selector switch. For the TS-352 B/U read the

dc scale for the range of the jack to which the red lead is connected.

For the

AN/URM-105, read the upper black straight lined portion of the ac and dc volts

scale for the range chosen by the selector switch.

(3) Electrical System - Problem: FUEL QUANTITY INDICATOR FAILS TO REGISTER WHEN

MASTER SWITCH IS ON, ALTHOUGH TANKS HOLD KNOWN QUANTITY OF FUEL.

(a) Find the name of the item that doesn't work.

For this example, the name of the item is the "Fuel Electrical System,"

and would be found on page 2-82, TM 9-2300-257-20.

(b) Find the problem with the item.

The problem to be rectified in this example is, FUEL QUANTITY INDICATOR

FAILS TO REGISTER WHEN MASTER SWITCH IS ON, ALTHOUGH TANKS HOLD KNOWN

QUANTITY OF FUEL, and would be found on page 2-82.1.