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

TASK 27-90-00-810-824-A
Loss of the ACS1 Signal of the ELAC2 MON Side and SEC2 MON Side

1. Possible Causes

ELAC-2 [2CE2]
SEC-2 [1CE2]
wiring of the ACS1 SPLY XDCR signal from the SEC2 MON side to the COM side
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 27-90-00-740-093-A

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

4. Fault Isolation
Subtask 27-90-00-810-072-A

A. If the ground scanning gives at least two maintenance messages of the list below:
L B ELEV MODE XDCR 34CE3
L ELEV POS MON XDCR OF ELAC2/SEC2
R B ELEV MODE XDCR 34CE4
R Y ELEV POS MON XDCR OF ELAC2/SEC2
ELAC2 MON OR INPUT OF THS ACTR XDCR1 9CE
SEC2 MON 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 AB/9E and the pin AB/9F ASM 279408:
(a) If the resistance value 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:
a Do a check of the wiring of the ACS1 SPLY XDCR signal from the SEC2 MON side to the COM side , pins AE/10D and AE/10E to pins AB/8E and AB/8F ASM 279408.

if the wiring is correct, go to Para. b_
if the wiring is not correct, repair the above wiring.

b Do a check and repair the wiring of the ACS1 SPLY XDCR signal from the SEC2 COM side to the first terminal block , pins AB/9E and AB/9F ASM 279408.

Subtask 27-90-00-740-094-A

B. Do the test given in Para. 3.

[Rev.8 from Aug 2018] 2026.04.04 04:39:12 UTC