Loss of the 115VAC Power Supply of the BSCU-SYS 1

TASK 32-42-00-810-824-A
Loss of the 115VAC Power Supply of the BSCU-SYS 1

1. Possible Causes

wiring from the BSCU (10GG) pin AB/15H to the ground terminal
BSCU [10GG]
wiring from the BSCU (10GG) pin AB/14H to the circuit breaker (1GG)
C/B-HYDRAULIC/BRAKING AND STEERING/SYS1/CTL [1GG]

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
ASM 324201
AMM 32-42-34-000-001	Removal of the Braking/Steering Control Unit (BSCU)
AMM 32-42-34-400-001	Installation of the Braking/Steering Control Unit (BSCU)
AMM 32-46-00-740-001	BITE Test of the BSCU

3. Fault Confirmation
Subtask 32-42-00-740-070-A

A. Test
(1) Do a reset of the BSCU with the A/SKID AND NOSE WHEEL switch (5GG).
(2) Do the BITE test with the BSCU channel that is the source of the fault message AMM 32-46-00-740-001.
(a) If the circuit breaker (1GG) is open:

refer to Para. 4.A.(2)

4. Fault Isolation
Subtask 32-42-00-810-073-A

A. If the BITE test is not available:

Do a check of the circuit breaker (1GG) status:

(1) If the circuit breaker is closed:

Do a check for 115VAC at pin AB/14H of the BSCU (10GG) ASM 324201.

(a) If there is 115VAC:

Do a check for a ground signal at pin AB/15H of the BSCU (10GG) ASM 324201.

1 If there is no ground signal:

Repair the wiring from the BSCU (10GG) pin AB/15H to the ground terminal ASM 324201.

2 If there is a ground signal:

Replace the BSCU [10GG] AMM 32-42-34-000-001 and AMM 32-42-34-400-001.

(b) If there is no 115VAC:

Do a check of the wiring from the BSCU (10GG) pin AB/14H to the circuit breaker (1GG) ASM 324201.

1 If there is no continuity:

Repair the related wiring.

2 If there is continuity:

Replace the C/B-HYDRAULIC/BRAKING AND STEERING/SYS1/CTL [1GG] ASM 324201.

(2) If the circuit breaker is opened:

Do a check for a short circuit to ground at the wiring from the BSCU (10GG) pin AB/14H to the circuit breaker (1GG) ASM 324201.

(a) If there is a short circuit to ground:

Repair the related wiring.

(b) If there is no short circuit to ground:

Replace the circuit breaker (1GG) ASM 324201.

Replace the BSCU (10GG) AMM 32-42-34-000-001 and AMM 32-42-34-400-001.

Subtask 32-42-00-740-071-A

B. Do the test given in Para. 3.A.

[Rev.8 from Aug 2018] 2026.04.04 04:31:32 UTC