Loss of the ACS1 Signal of the SEC1 MON Side

TASK 27-90-00-810-818-A
Loss of the ACS1 Signal of the SEC1 MON Side

1. Possible Causes

ELAC-1 [2CE1]
SEC-1 [1CE1]
wiring of the ACS1 SPLY XDCR signal from the SEC1 MON side to the COM side
wiring of the ACS1 SPLY MON signal from the SEC1 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 279407
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 27-90-00-740-083-A

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

4. Fault Isolation
Subtask 27-90-00-810-067-A

A. If the ground scanning gives at least two maintenance messages of the list below:
SEC1 OR WIRING FROM L ELEV POS MON XDCR
SEC1 OR WIRING FROM R ELEV POS MON XDCR
SEC1 MON OR WIRING FROM THS ACTR XDCR2 9CE
SEC1 OR WIRING FROM L G ELEV MODE XDCR 34CE1
SEC1 OR WIRING FROM R Y ELEV MODE XDCR 34CE2
(1) Remove the ELAC1 AMM 27-93-34-000-001 and the SEC1 AMM 27-94-34-000-001.
(2) At the SEC1 receptacle, do a check of the resistance between the pin AB/9E and the pin AB/9F ASM 279407:
(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-1 [2CE1] AMM 27-93-34-000-001 and AMM 27-93-34-400-001.
3 Replace the SEC-1 [1CE1] AMM 27-94-34-000-001 and AMM 27-94-34-400-001.
(b) If the resistance is more than 10 Ohms:

do a check of the wiring of the ACS1 SPLY XDCR signal from the SEC1 MON side to the COM side :
. pins AE/10E and AE/10D to pins AB/8E and AB/8F ASM 279407.

1 If the wiring is not correct:

repair it
install the ELAC1 AMM 27-93-34-400-001 and the SEC1 AMM 27-94-34-400-001.

a If the fault continues:

replace the SEC-1 [1CE1] AMM 27-94-34-000-001 and AMM 27-94-34-400-001.

2 If the wiring is correct:
a Replace the SEC-1 [1CE1] AMM 27-94-34-000-001 and AMM 27-94-34-400-001.
b Install the ELAC1 AMM 27-93-34-400-001.
c If the fault continues:

do a check and repair the wiring of the ACS1 SPLY MON signal from the SEC1 COM side to the first terminal block , pins AB/9E and AB/9F ASM 279407.
if the wiring is correct, do the failure of an alternating current supply (ACS) procedure (Ref. TSM TASK 27-90-00-810-801).

Subtask 27-90-00-740-084-A

B. Do the test given in Para. 3.

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