Ignitor A Supply Fault on EIU-1

TASK 73-25-00-810-B05-A
Ignitor A Supply Fault on EIU-1

1. Possible Causes

aircraft wiring
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 743101

3. Fault Confirmation
Subtask 73-25-00-710-544-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

WARNING: MAKE SURE THAT THE CIRCUIT BREAKERS ARE OPEN BEFORE YOU DO MAINTENANCE WORK ON THIS SYSTEM WIRING. THE VOLTAGE ON THIS SYSTEM IS DANGEROUSLY HIGH AND CAN CAUSE SEVERE INJURY.

Subtask 73-25-00-810-410-A ** ON A/C NOT FOR ALL

A. If there is confirmation of the fault:
(1) Check on report for any failure of busbar (401XP).
(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 fault continues, go to the Para. 4.

Subtask 73-25-00-865-138-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)
49VU	ENGINE/1 AND 2/IGN/SYS A	1JH	A03

Subtask 73-25-00-810-411-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 115 VAC supply circuits AWM 743101. 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: Ignitor system A circuit connector contacts

C/B (1JH) Contacts	EIU-1 (1KS1) Connector AC Contacts
2	4

(3) If a problem is found, repair or replace aircraft wiring AWM 743101.
(4) 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 73-25-00-865-139-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)
49VU	ENGINE/1 AND 2/IGN/SYS A	1JH	A03

5. Close-up
Subtask 73-25-00-860-142-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