Loss of Vibration Indications on Both Engines

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1. Possible Causes
· EVMU ( 2EV )
· wiring from the circuit breaker 1EV to the pin AC/2 of the EVMU (2EV)
· C/B-ENGINE/ENG1 AND 2/EVMU ( 1EV )
2 Job Set-up Information
A. Referenced Information
REFERENCE DESIGNATION
Ref. ASM 77-32-02
Ref. AMM 77-32-34-000-041 Removal of the Engine Vibration Monitoring Unit (EVMU)
Ref. AMM 77-32-34-400-041 Installation of the Engine Vibration Monitoring Unit (EVMU)
Ref. AMM 77-32-34-710-041 Operational Check of EVMU through CFDS
3. Fault Confirmation
Subtask 77-30-00-710-072-A
A. Test
(1) Do the operational test of the Engine Vibration Monitoring Unit (EVMU) through the Centralized Fault
Display System (CFDS) Ref. AMM 77-32-34-710-041 .
4. Fault Isolation
Subtask 77-30-00-865-055-A
A. Table of the circuit breakers used in this procedure:
PANEL DESIGNATION FIN LOCATION
121VU ENGINE/ENG1 AND 2/EVMU 1EV R44
Subtask 77-30-00-810-062-A
B. If the operational test gives the maintenance message EVMU:
· do a check of the circuit breaker 1EV status.
(1) If the circuit breaker is open:
· close the circuit breaker 1EV.
(2) If the circuit breaker is closed:
· do a check for 115VAC on the pin AC/2 of the EVMU Ref. ASM 77-32-02.
(a) If there is 115VAC:
· replace the EVMU ( 2EV ) , Ref. AMM 77-32-34-000-041 and Ref. AMM 77-32-34-400-041 .
(b) If there is no 115VAC:
· do a check and repair the wiring from the circuit breaker 1EV to the pin AC/2 of the EVMU
(2EV) , Ref. ASM 77-32-02.
1 If the fault continues:
· replace the C/B-ENGINE/ENG1 AND 2/EVMU ( 1EV ) .
Subtask 77-30-00-710-073-A
C. Do the test given in Para. 3. [Rev.6 from Feb 2017] 2026.04.04 04:37:52 UTC