1-107 TEST ENGINE (AVIM) (Continued)
c. If level of vibration varies with N2 speed, check power turbine assembly for damage and improper
runouts and blade tip clearances. Replace or repair as necessary.
d. If level of vibration varies with N1 speed, check gas producer and compressor sections for damage
and improper runouts and blade tip clearances.
e. If engine vibration exceeds limits after performing preceding steps c. and d., forward engine to a
higher level of maintenance. Ensure that the completed vibration test data sheets are kept with
8. VIBRATION METER CHECK
Recheck adjustment of vibration meter after the vibration test.
To ensure accuracy of vibration test, adjust vibration meter using
same power source that is to be used during vibration test. Inac-
curate readings may result.
Vibration meter must contain a 70 Hz high pass fitter in INPUT
socket 1 and a 200 Hz filter in INPUT socket 2; initial preparations
of vibration meter may require installation of filters LTCT23842-01
a. If battery power supply LTCT22030-01 is used, proceed as follows:
(1) Set SELECTOR switch to OFF. Battery voltage is sufficient when meter reading on 0 to 5 scale
is one volt or greater.
(2) Set SELECTOR switch to BATT. Any battery voltage must be one volt or greater.
b. Check continuity of transducer circuits by placing RANGE switch to 500, setting SELECTOR switch
to CONT., and depressing selected channels on CHANNEL SELECTOR lf circuit is satisfactory,
meter will read within green zone. If channel is open, indicator will deflect full scale. When circuit is
shorted, indication should zero.
c. Set SELECTOR switch to CA LIB and adjust OSC LEVEL for full scale meter deflection.
d. Set SELECTOR switch to SENS ADJ.
e. Depress CHANNEL SELECTOR 1 and set SENSITIVITY control to 10.5 indication on 0 to 15 scale.
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