DOC AIRBUS | TSM A320FLoss of the N1 Vibration Indication on Engine 1
TASK 77-30-00-810-805-A
Loss of the N1 Vibration Indication on Engine 1
1. Possible Causes
A. Referenced Information
3. Fault Confirmation
Subtask 77-30-00-710-055-A ** ON A/C NOT FOR ALL
Subtask 77-30-00-810-053-A ** ON A/C NOT FOR ALL
[Rev.8 from Aug 2018]
2026.04.04 04:37:47 UTC
Loss of the N1 Vibration Indication on Engine 1
1. Possible Causes
wiring from the EVMU (2EV) to the N1 speed sensor (4000EV) - EVMU [2EV]
- SENSOR-N1 ROTATIONAL SPD [4000EV]
- harness between the EVMU and the N1 speed sensor
A. Referenced Information
| REFERENCE | DESIGNATION |
|---|---|
| AMM 71-00-00-710-009 | Vibration Check |
| AMM 77-11-10-000-001 | Removal of the N1 Speed Sensor |
| AMM 77-11-10-000-002 | Removal of the N1 Speed Sensor |
| AMM 77-11-10-400-001 | Installation of the N1 Speed Sensor |
| AMM 77-11-10-400-002 | Installation of the N1 Speed Sensor |
| 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) |
Subtask 77-30-00-710-055-A ** ON A/C NOT FOR ALL
A. Test
Not applicable, you cannot confirm this fault on the ground.
4. Fault IsolationNot applicable, you cannot confirm this fault on the ground.
Subtask 77-30-00-810-053-A ** ON A/C NOT FOR ALL
A. If the Post Flight Report gives the maintenance message ENG1 N1 SPEED SENSOR:
Subtask 77-30-00-810-053-B ** ON A/C NOT FOR ALL - do a check for open or short to ground of the
wiring from the EVMU (2EV) to the N1 speed sensor (4000EV) pins AA/8B, 7A to pins CC/1, 2 ASM 773202.
- repair the above wiring.
- with the cable disconnected from the EVMU, do a resistance check of the EVMU between:
pins 8B and 7A (40 to 80 Ohms).
- replace the EVMU [2EV] AMM 77-32-34-000-040 and AMM 77-32-34-400-040.
- with the connector CC disconnected from the N1 speed sensor, do a resistance check of the sensor between:
pins 1 and 2 (40 to 80 Ohms).
- replace the SENSOR-N1 ROTATIONAL SPD [4000EV] AMM 77-11-10-000-001 and AMM 77-11-10-400-001.
- replace the harness between the EVMU and the N1 speed sensor ASM 773202.
A. If the Post Flight Report gives the maintenance message ENG1 N1 SPEED SENSOR:
Subtask 77-30-00-710-056-A ** ON A/C NOT FOR ALL - do a check for open or short to ground of the
wiring from the EVMU (2EV) to the N1 speed sensor (4000EV) pins AA/8B, 7A to pins CC/1, 2 ASM 773202.
- repair the above wiring.
- with the cable disconnected from the EVMU, do a resistance check of the EVMU between:
pins 8B and 7A (40 to 80 Ohms).
- replace the EVMU [2EV] AMM 77-32-34-000-042 and AMM 77-32-34-400-042.
- with the connector CC disconnected from the N1 speed sensor, do a resistance check of the sensor between:
pins 1 and 2 (40 to 80 Ohms).
- replace the SENSOR-N1 ROTATIONAL SPD [4000EV] AMM 77-11-10-000-002 and AMM 77-11-10-400-002.
- replace the harness between the EVMU and the N1 speed sensor ASM 773202.