Loss of the ACS1 Signal of the ELAC2 COM Side and SEC2 COM Side

TASK 27-90-00-810-823-A
Loss of the ACS1 Signal of the ELAC2 COM Side and SEC2 COM Side

1. Possible Causes

ELAC-2 [2CE2]
SEC-2 [1CE2]
wiring of the ACS1 SPLY XDCR signal from the SEC2 COM side to the first terminal block

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
TSM TASK 27-90-00-810-801-A	Failure of an Alternating Current Supply (ACS)
AMM 27-93-34-000-001	Removal of the ELAC
AMM 27-93-34-400-001	Installation of the ELAC
ASM 279408
AMM 27-94-34-000-001	Removal of the SEC
AMM 27-94-34-400-001	Installation of the SEC
AMM 27-96-00-740-001	BITE Test of the EFCS (Ground Scanning)

3. Fault Confirmation
Subtask 27-90-00-740-095-A

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

4. Fault Isolation
Subtask 27-90-00-810-073-A

A. If the ground scanning gives at least two maintenance messages of the list below:
L G ELEV POS XDCR 34CE1 COM E2/S2 : USE STBY XDCR
R Y ELEV POS XDCR 34CE2 COM E2/S2 : USE STBY XDCR
ELAC2 COM OR INPUT OF THS ACTR XDCR1 9CE
SEC2 COM OR INPUT OF THS ACTR XDCR3 9CE
(1) Remove the ELAC2 AMM 27-93-34-000-001 and the SEC2 AMM 27-94-34-000-001.
(2) At the SEC2 receptacle, do a check of the resistance between the pin AA/12F and the pin AA/12G ASM 279408:
(a) If the resistance is less than 10 Ohms:
1 Do this procedure (Ref. TSM TASK 27-90-00-810-801).
2 Replace the ELAC-2 [2CE2] AMM 27-93-34-000-001 and AMM 27-93-34-400-001.
3 Replace the SEC-2 [1CE2] AMM 27-94-34-000-001 and AMM 27-94-34-400-001.
(b) If the resistance is more than 10 Ohms:
1 Replace the SEC-2 [1CE2] AMM 27-94-34-000-001 and AMM 27-94-34-400-001.
Install the ELAC2 AMM 27-93-34-400-001.
2 If the fault continues:

do a check and repair the wiring of the ACS1 SPLY XDCR signal from the SEC2 COM side to the first terminal block , pins AA/12F and AA/12G ASM 279408.
if the wiring is correct, do the failure of an alternating current supply (ACS) procedure (Ref. TSM TASK 27-90-00-810-801).

Subtask 27-90-00-740-096-A

B. Do the test given in Para. 3.

[Rev.8 from Aug 2018] 2026.04.04 04:27:53 UTC