Loss of the Output B Bus on EIU 2

TASK 73-20-00-810-846-A
Loss of the Output B Bus on EIU 2

1. Possible Causes

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
AMM 31-50-00-710-001	Ground Scanning of the Central Warning System
AMM 73-21-60-000-001	Removal of the Electronic Control Unit (ECU)
AMM 73-21-60-400-001	Installation of the Electronic Control Unit (ECU)
ASM 732505
ASM 732506
AMM 73-25-34-000-040	Removal of the Engine Interface Unit (EIU)
AMM 73-25-34-400-040	Installation of the Engine Interface Unit (EIU)

3. Fault Confirmation
Subtask 73-20-00-865-059-A ** ON A/C NOT FOR ALL

A. Make sure that this(these) circuit breaker(s) is(are) closed:

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
49VU	ENGINE/2/FADEC A/AND EIU 2	2KS2	A05
121VU	ENGINE/ENG2/FADEC B/AND EIU 2	4KS2	Q40

Subtask 73-20-00-710-110-A ** ON A/C NOT FOR ALL

B. Do the operational test of the Central Warning Systems (FWC) AMM 31-50-00-710-001.

4. Fault Isolation
Subtask 73-20-00-810-096-A ** ON A/C NOT FOR ALL

A. If the test gives the maintenance message FWC1 : NO DATA FROM EIU2:

(1) If there is 28VDC:

(2) If the fault continues:

do a check and repair the wiring from the EIU 2 (1KS2) pins AB/5H, 5K to the first terminal block ASM 732506.

(3) If the fault continues:

Subtask 73-20-00-710-111-A ** ON A/C NOT FOR ALL

B. Do the test given in Para. 3.

[Rev.8 from Aug 2018] 2026.04.04 04:35:19 UTC