1 If one of these measurements is less than 20 megohms:
_ - the sensor is not serviceable.
 2 If one of the two vibration sensors is found not serviceable:
_
 - configure the MCDU to read the other vibration sensor output (Ref. AMM TASK 77-32-34-860-041).
 NOTE : If the TRF vibration sensor is not serviceable, it
____ should be replaced (Ref. AMM TASK 77-31-30-000-002) and (Ref. AMM TASK 77-31-30-400-002).
 NOTE : The No. 1 bearing vibration sensor cannot be replaced
____
 on-wing.

 (d) If nothing is found:

 - do the operational test of the Engine Vibration Monitoring Unit (EVMU) through the Centralized Fault Display System (CFDS) (Ref. AMM TASK 77-32-34-710-040).

 (e) If nothing is found:

 - configure the MCDU to read the other vibration sensor output (Ref. AMM TASK 77-32-34-860-041).
 (2) If the engine core vibration level has significantly increased since the engine was installed: - open the cowlings (Ref. AMM TASK 71-11-00-210-001) and do a visual
 inspection around the engine (centerbody plug, piping and brackets fan cowl and core cowl area).
 (a) Do a check and an inspection of the accessories and QEC components. This includes the check and inspection of:
 - the accessory gear box mounts,

 - the link and brackets of the accessories to make sure they are loose or broken,

 - the cowling brackets, hinges and rigging,

 - the pneumatic system for correct condition and rigging.

 1 If the check is not correct:
_
 - repair or replace as required.
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 (b) Do a check of the electric master magnetic chip detector visual indicator (Ref. AMM TASK 79-35-00-040-042) and the magnetic chip detector (Ref. AMM TASK 79-00-00-281-002) and the scavenge screen plugs (Ref. AMM TASK 79-00-00-281-003).
 1 If you find magnetic particles:
_
 - follow the related instructions per (Ref. AMM TASK 79-00-00-281-002) and NDT Manual (section CHIP ANALYSIS).
 2 If no magnetic particles are found:
_
 - do a borescope inspection of the high pressure compressor rotor assembly (Ref. AMM TASK 72-31-00-290-002) and of the high pressure turbine blades (Ref. AMM TASK 72-52-00-290-001).
 (c) If nothing is found:
 1 Do a check of the wiring, connectors and receptacles (Ref. ASM
_
 77-32/02) between:

 - the No. 1 bearing vibration sensor (4002EV) and the EVMU (2EV),

 - the TRF vibration sensor (4003EV) and the EVMU (2EV).

 2 Disconnect the harnesses from the No. 1 bearing and the TRF
_
 sensors,

 - do a check for damaged pins or connector oxidation (Ref. AMM TASK 71-50-00-210-001).
 a If damage is found:
_
 - repair or replace as required.
 b If no damage is found:
_
 - do a cleaning of the connectors using a bristle brush with stoddard solvent (Material No. CP2011) (Ref. AMM TASK 73-21-50-210-002).
 3 Do an electrical test of the No. 1 bearing vibration sensor
_ and the TRF vibration sensor:
 - disconnect the aircraft harness from the vibration sensor connectors. If necessary, use soft nose pliers.

 - measure the insulation resistance with a megohmeter 0-100 megohms, V=45VDC between: . pins 1 and 2 . pins 1 and 3 . pin 2 and connector body . pin 3 and connector body, the insulation resistance is expected to be greater than 20 megohms.

 a If one of these measurements is less than 20 megohms:
_
 - the sensor is not serviceable.
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 F 『 E C F M E E E E 56 E E E b If one of the two vibration sensors is found not

_
 serviceable:

 - configure the MCDU to read the other vibration sensor output (Ref. AMM TASK 77-32-34-860-041).
 NOTE : If the TRF vibration sensor is not serviceable, it
____ should be replaced (Ref. AMM TASK 77-31-30-000-002) and (Ref. AMM TASK 77-31-30-400-002).
 NOTE : The No. 1 bearing vibration sensor cannot be
____ replaced on-wing.
 (d) If nothing is found:

 - do the operational test of the Engine Vibration Monitoring Unit (EVMU) through the Centralized Fault Display System (CFDS) (Ref. AMM TASK 77-32-34-710-040).

 (e) If nothing is found:

 - Contact CFM to confirm high vibration level
　
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