Loss of the EVMU Output Bus

TASK 77-30-00-810-830-A
Loss of the EVMU Output Bus

1. Possible Causes

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
AMM 31-32-00-869-002	Procedure for the Class 3 Fault Reading
ASM 773202
AMM 77-32-34-000-040	Removal of the Monitoring Unit Engine Vibration (EVMU)
AMM 77-32-34-000-042	Removal of the Engine Vibration Monitoring Unit (EVMU)
AMM 77-32-34-400-040	Installation of the Vibration Monitoring Unit (EVMU)
AMM 77-32-34-400-042	Installation of the Engine Vibration Monitoring Unit (EVMU)

3. Fault Confirmation
Subtask 77-30-00-865-050-A ** ON A/C NOT FOR ALL

A. Make sure that this(these) circuit breaker(s) is(are) closed:

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
121VU	ENGINE/ENG1 AND 2/EVMU	1EV	R44

Subtask 77-30-00-740-050-A ** ON A/C NOT FOR ALL

B. Test
On the CFDS MENU page, get access to the AVIONICS STATUS page AMM 31-32-00-869-002.

4. Fault Isolation
Subtask 77-30-00-810-075-A ** ON A/C NOT FOR ALL

A. If the test gives the maintenance message NO EVMU DATA:

(1) If the fault continues:

do a check and repair the wiring from the EVMU (2EV) pins AA/13A, 13C to the first terminal block ASM 773202.

Subtask 77-30-00-810-075-B ** ON A/C NOT FOR ALL

A. If the test gives the maintenance message NO EVMU DATA:

(1) If the fault continues:

do a check and repair the wiring from the EVMU (2EV) pins AA/13A, 13C to the first terminal block ASM 773202.

Subtask 77-30-00-740-051-A ** ON A/C NOT FOR ALL

B. Do the test given in Para. 3.

[Rev.8 from Aug 2018] 2026.04.04 04:37:47 UTC