ICU B Supply Fault on EIU-1

TASK 73-25-00-810-B03-A
ICU B Supply Fault on EIU-1

1. Possible Causes

EIU-1 [1KS1]

2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment

REFERENCE	QTY	DESIGNATION
No specific	1	MULTIMETER - STANDARD
No specific	AR	SAFETY CLIP - CIRCUIT BREAKER

B. Referenced Information

REFERENCE	DESIGNATION
AMM 73-25-34-000-802	Removal of the Engine Interface Unit (EIU)
AMM 73-25-34-400-802	Installation of the Engine Interface Unit (EIU)
AMM 73-25-34-710-802	Operational Test of the Engine Interface Unit (EIU) with the Centralized Fault Display System (CFDS)
AWM 783604

3. Fault Confirmation
Subtask 73-25-00-710-542-A ** ON A/C NOT FOR ALL

A. Do the operational test of the Engine Interface Unit (EIU) with the Centralized Fault Display System (CFDS) to confirm this fault AMM 73-25-34-710-802.

4. Fault Isolation
Subtask 73-25-00-810-406-A ** ON A/C NOT FOR ALL

A. If there is confirmation of the fault:
(1) Check on report for any failure of normal busbar (103PP).
(a) Troubleshoot as necessary (Ref. TSM Chap. 24).
(b) Do the test given in Para. 3.
(c) If no fault regarding the busbar is reported or if the fault continues, go to the Para. 4.B.

Subtask 73-25-00-865-134-A ** ON A/C NOT FOR ALL

B. Open, safety and tag this(these) circuit breaker(s):

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
FOR FIN: 4020KM1 (POWER PLANTDEMOUNTABLE, ENG 1)
121VU	ICU B/ENG1 PWR SPLY	101KS1	R42

Subtask 73-25-00-810-407-A ** ON A/C NOT FOR ALL

C. If no fault regarding the busbar is reported or if fault continues:
(1) Remove EIU-1 (1KS1) AMM 73-25-34-000-802.
(2) Use a MULTIMETER - STANDARD to test the 28 VDC supply circuits AWM 783604. Refer to table 1. Look for:
(a) Wire-to-wire shorts
(b) Shorts to ground
(c) Continuity (less than 5 ohms resistance).

NOTE: A short to ground is found when the resistance is less than 100 000 (100K) ohms.

Table 1: 28 VDC circuit connector contacts

C/B (101KS1) Contacts	EIU-1 (1KS1) Connector AB Contacts
2	13C

(3) If no problem is found or if fault continues:
(a) Replace EIU-1 [1KS1] AMM 73-25-34-400-802.
(b) Close circuit breakers. Refer to the Para.4.D.
(c) Do the test given in Para. 3.

Subtask 73-25-00-865-135-A ** ON A/C NOT FOR ALL

D. Remove the safety clip(s) and the tag(s) and close this(these) circuit breaker(s):

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
FOR FIN: 4020KM1 (POWER PLANTDEMOUNTABLE, ENG 1)
121VU	ICU B/ENG1 PWR SPLY	101KS1	R42

5. Close-up
Subtask 73-25-00-860-158-A ** ON A/C NOT FOR ALL

A. Put the aircraft back to its initial configuration.
(1) Make sure that the work area is clean and clear of tools and other items.

[Rev.8 from Aug 2018] 2026.04.04 04:36:49 UTC