Failure of the Left Blue Elevator-Servocontrol Servovalve

TASK 27-30-00-810-806-A
Failure of the Left Blue Elevator-Servocontrol Servovalve

1. Possible Causes

servovalve of the servocontrol 34CE3
XDCR UNIT-ELEV POS, L [49CE1]
The wiring of the SV signal from the servocontrol (34CE3) to the first terminal block
The wiring of the SV XDCR (LVDT) signal from the servocontrol (34CE3) to the first terminal block
The wiring of the POS XDCR COM (RVDT) V1, V2 signals from the servocontrol (34CE3) to the first terminal block
The wiring of the POS XDCR MON (RVDT) V1, V2 from the transducer unit (49CE1), plug B to the first terminal block

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
AMM 27-34-51-000-008	Removal of the Elevator Servo Control Actuator Servo Valve
AMM 27-34-51-400-003	Installation of the Elevator Servo Control Actuator Servo Valve
AMM 27-92-13-000-001	Removal of the Elevator Position Transducer-Unit
AMM 27-92-13-400-001	Installation of the Elevator Position Transducer-Unit
ASM 279307
AMM 27-96-00-710-020	Operational Test of the Side Stick Assembly (Activation for the BITE Test)
AMM 27-96-00-740-001	BITE Test of the EFCS (Ground Scanning)

3. Fault Confirmation
Subtask 27-30-00-700-056-A

A. Test
(1) Do the operational test of the side stick assembly (Activation for the BITE test) AMM 27-96-00-710-020.
(2) Do the BITE test of the EFCS (ground scanning) AMM 27-96-00-740-001.

4. Fault Isolation
Subtask 27-30-00-810-053-A

A. If the test gives the maintenance message:
L B ELEV SERVO VLV 34CE3

Replace the servovalve of the servocontrol 34CE3 AMM 27-34-51-000-008 and AMM 27-34-51-400-003.

NOTE: The resistance of the servovalve (connector A between pin D and pin E) must be 500 ohms +/- 10 %.

Subtask 27-30-00-810-108-A

B. If the fault continues:
(1) Replace the XDCR UNIT-ELEV POS, L [49CE1] AMM 27-92-13-000-001 and AMM 27-92-13-400-001.

Subtask 27-30-00-810-103-A

C. If the fault continues:
(1) Do a check and repair:
(a) The wiring of the SV signal from the servocontrol (34CE3) to the first terminal block ASM 279307.
(b) The wiring of the SV XDCR (LVDT) signal from the servocontrol (34CE3) to the first terminal block ASM 279307.
(c) The wiring of the POS XDCR COM (RVDT) V1, V2 signals from the servocontrol (34CE3) to the first terminal block ASM 279307.
(d) The wiring of the POS XDCR MON (RVDT) V1, V2 from the transducer unit (49CE1), plug B to the first terminal block ASM 279307.

Subtask 27-30-00-700-057-A

D. Do the tests given in Para. 3.

[Rev.8 from Aug 2018] 2026.04.04 04:27:30 UTC