TM 55-4920-328-13
I. Repeat steps (a) through (k) for any transducers of
the same type suspected to be malfunctioning.
m. Depressurize and remove the pressure source.
n. Deenergize the ENGINE DC switchlight unit and
CONSOLE DC switchlight unit on services panel 4A1.
o. Deenergize all system power.
5-10. Checkout of Synchronous Type Pressure
Transmitters 11MT5 Through 11MT14.
Pressure transmitters 11MT5 through 11MT14 are
synchronous type units which provide phase-relation
signals to synchronous indicators. The output signal of
the transmitter cannot be measured in terms of signal
voltage magnitude; therefore, an operational check of
an isolated transmitter is not possible. A faulty
transmitter may be found by the substitution method
outlined in the following text. Care must be exercised
when substituting one transmitter for another to use a
substitute transmitter of the same full scale pressure
range, to provide a full scale pressure indication of the
synchronous indicator in the circuit being checked by
this method. A typical procedure is as follows:
a. When pressure transmitter 11MT5 is suspected of
faulty operation, remove connector 11 P5 from the
transmitter.
b. Remove 11P6 from transmitter 11MT6.
c. Connect 11P5 to transmitter 11MT6. (This action
will provide an alternate signal source for the torque oil
pressure system shown in figure FO-11 located in the
back of this manual.)
d. Connect the test trailer air system as specified in
paragraph 5-8,d.
e. Energize the METS electrical systems as outlined
in chapter 2. Preliminary Checkout Prior to Test
paragraph.
f. Energize the ENGINE DC switchlight unit (27,
figure 1-25), the CONSOLE DC switchlight unit (30), and
the 26 VAC 400 HZ switchlight unit (31). Allow the
specified 30-minute warmup period.
g. Vent the pressure transmitter 11MT6, observe
torque pressure indicator 3A1M1 (2, figure 1-24) for an
indication of 0 psig. If not, adjust the ZERO ADJ. in the
data selector assembly 1A2.
h. Apply an inlet pressure of 200 psig to transmitter
11MT6, by adjusting pressure regulator and observing
gage on pneumatic panel 9A2.
i. Observe torque pressure indicator 3A1M1 indicates
200 2 psig. If approximately 200 psig is displayed on
the indicator, transmitter 11MT5 is defective. If no
pressure is displayed on the indicator, the trouble in the
torque oil pressure circuit is downstream from the
substitute transmitter. Refer to paragraph 5-28 for
troubleshooting procedures for the torque oil pressure
system.
j. Depressurize and remove test connections.
k. Deenergize the ENGINE DC switchlight unit, the
CONSOLE DC switchlight unit, and the 26 VAC 400 HZ
switchlight unit. Do not deenergize the METS primary
power source at this time.
I. Detach connector 11P5 from transmitter 11MT6
and reinstall 11P6 on 11MT6.
m. Remove 11MT5, if found defective, and install a
new transmitter of like part number in the data
acquisition assembly.
n. To use the foregoing instructions to detect a faulty
synchronous
transmitter,
substitute
a
pressure
transmitter of the same full scale pressure rating for that
of the suspect unit. As an example, transmitters
11MT5,
11MT6,
11MT9,
and
11MT10
may
be
interchanged without regard for differences of inlet
pressure rating. (Refer to figures FO-11 and FO-13.)
Transmitters
11MT7
and
11MT8
may
also
be
interchanged by the substitution method outlined in the
preceding typical procedures. Likewise, transmitters 1
1MT12, 11MT13, and 11MT14 may be interchanged.
Transmitter 11MT11 (which has a different rating) may
be interchanged with any other transmitter in Unit 11
provided that the inlet pressure applied to the substitute
transmitter corresponds to the full scale pressure range
of that transmitter and not that of 11MT11, to provide a
full scale display on the applicable synchronous
indicator.
5-11.Checkout of T55-L11 Electric Torque System.
If trouble is encountered during test of a T55 engine,
refer to paragraph 5-33.
5-6
