Hydraulic Pump Depressurization Supply Fault on EIU-2

TASK 73-25-00-810-B28-A
Hydraulic Pump Depressurization Supply Fault on EIU-2

1. Possible Causes

EIU-2 [1KS2]

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
AWM 291301
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)

3. Fault Confirmation
Subtask 73-25-00-710-567-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 73-25-00-810-450-A ** ON A/C NOT FOR ALL

A. If there is confirmation of the fault:
(1) Check on report for any failure of essential BUS bar (401PP).
(a) Troubleshoot as necessary (Ref. TSM Chap 24).
(2) Check on report for any failure of normal BUS bar (202PP).
(a) Troubleshoot as necessary (Ref. TSM Chap 24).
(3) Do the test given in Para. 3.
(4) If no fault regarding the BUS bar is reported or if fault continues, go to the Para. 4.B.

Subtask 73-25-00-865-172-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: 4020KM2 (POWER PLANTDEMOUNTABLE, ENG 2)
49VU	HYDRAULIC/Y HYD/PUMP ENG2 ALT	3710GD	H02
121VU	HYDRAULIC/Y HYD/PUMP ENG2/CTL	3701GD	Q36

Subtask 73-25-00-810-451-A ** ON A/C NOT FOR ALL

C. If no fault regarding the BUS bar is reported or if fault continues:
(1) Remove EIU-2 [1KS2] AMM 73-25-34-000-802.
(2) Use a MULTIMETER - STANDARD to do a test of the 28 VDC supply circuits AWM 291301. Refer to Table 1 and Table 2. 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 (3710GD) Contacts	EIU-2 (1KS2) Connector AB Contacts
2	13J

Table 2: 28 VDC Circuit Connector Contacts

C/B (3701GD) Contacts	EIU-2 (1KS2) Connector AN Contacts
2	13J

(3) If no problem is found or if the fault continues:
(a) Replace EIU-2 [1KS2] AMM 73-25-34-400-802.
(b) Close the circuit breakers. Refer to the Para. 4.D.
(c) Do the test given in Para. 3.

Subtask 73-25-00-865-173-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: 4020KM2 (POWER PLANTDEMOUNTABLE, ENG 2)
49VU	HYDRAULIC/Y HYD/PUMP ENG2 ALT	3710GD	H02
121VU	HYDRAULIC/Y HYD/PUMP ENG2/CTL	3701GD	Q36

5. Close-up
Subtask 73-25-00-860-173-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 04:36:50 UTC