Failure of the THS Actuator Servo Motor 1

TASK 27-93-00-810-837-A
Failure of the THS Actuator Servo Motor 1

1. Possible Causes

RELAY-PITCH TRIM ACTUATOR MOTOR 1 SPLY [36CE1]
ELAC-2 [2CE2]
Electronic module 1
wiring of the K3-1 signal from the ELAC 2 (2CE2) to the first terminal block
wiring of the DSI-49 signal from the ELAC 2 (2CE2) to the ELAC 2 (2CE2)
wiring of the enable signal from the THS actuator (9CE) to the ELAC 2 (2CE2)
wiring of the enable signal from the THS actuator (9CE) to the ground
wiring from the relay (36CE1) to the ELAC 2 (2CE2) and to the THS actuator (9CE)
wiring of the fault signal from the THS actuator to the ELAC 2 (2CE2)
pitch trim actuator

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
AMM 24-41-00-861-002	Energize the Aircraft Electrical Circuits from the External Power
AMM 27-44-57-000-001	Removal of the Pitch Trim Actuator from the THS Actuator
AMM 27-44-57-000-002	Removal of the Electronic Modules of the Pitch Trim Actuator
AMM 27-44-57-400-001	Installation of the Pitch Trim Actuator to the THS Actuator
AMM 27-44-57-400-002	Installation of the Electronic Modules of the Pitch Trim Actuator
AIPC 27920803
ASM 279313
AMM 27-93-34-000-001	Removal of the ELAC
AMM 27-93-34-400-001	Installation of the ELAC
AMM 27-96-00-740-001	BITE Test of the EFCS (Ground Scanning)
AMM 29-10-00-864-001	Depressurize the Green Hydraulic System
AMM 29-10-00-864-002	Depressurize the Yellow Hydraulic System
AMM 29-10-00-864-003	Depressurize the Blue Hydraulic System

3. Fault Confirmation
Subtask 27-93-00-700-086-A

A. Test
(1) Energize the aircraft electrical circuits
AMM 24-41-00-861-002.
(2) Make sure that the Green, Blue and Yellow hydraulic systems are not pressurized AMM 29-10-00-864-001, AMM 29-10-00-864-003 and AMM 29-10-00-864-002.
(3) On the panel 24VU:

release the FLT CTL/ELAC2 pushbutton switch.(On this pushbutton switch, the OFF legend comes on).

(4) Wait 30 seconds.
(5) On the panel 24VU:

push the FLT CTL/ELAC2 pushbutton switch.(On this pushbutton switch, the OFF legend goes off).

(6) Do the BITE test of the EFCS (ground scanning) AMM 27-96-00-740-001.

NOTE: Wait 60 seconds before you start the BITE test.

4. Fault Isolation
Subtask 27-93-00-810-086-A

A. If the BITE test gives the maintenance message:
THS ACTR SERVO MOT1 9CE
(1) Remove the RELAY-PITCH TRIM ACTUATOR MOTOR 1 SPLY [36CE1] AIPC 27920803.
(2) Do a check of the resistance between pins X1 and X2 of the relay ASM 279313 .
(a) If the resistance is less than 280 ohms:

replace the RELAY-PITCH TRIM ACTUATOR MOTOR 1 SPLY [36CE1]
replace the ELAC-2 [2CE2] AMM 27-93-34-000-001 and AMM 27-93-34-400-001.

(b) If the resistance is more than 400 ohms:

replace the RELAY-PITCH TRIM ACTUATOR MOTOR 1 SPLY [36CE1] .

install the RELAY-PITCH TRIM ACTUATOR MOTOR 1 SPLY [36CE1]
go to Para (3).

(3) If the fault continues:

replace the ELAC-2 [2CE2] AMM 27-93-34-000-001 and AMM 27-93-34-400-001.

(4) If the fault continues:

replace the RELAY-PITCH TRIM ACTUATOR MOTOR 1 SPLY [36CE1] AIPC 27920803.

(5) If the fault continues:

replace the Electronic module 1 AMM 27-44-57-000-002 and AMM 27-44-57-400-002.

(6) If the fault continues:

do a check of the wiring of the K3-1 signal from the ELAC 2 (2CE2) to the first terminal block, COM part and MON part ASM 279313.