No Automatic Connection of the IDG 1 or Loss of the GEN 1

TASK 24-21-00-810-840-A
No Automatic Connection of the IDG 1 or Loss of the GEN 1

1. Possible Causes

wiring
IDG [4000XU]
GCU-1 [1XU1]
IDG-ENG 1 [4000XU1]

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
ASM 242101
AMM 24-21-51-000-040	Removal of the Integrated Drive Generator - IDG 1(2)
AMM 24-21-51-000-803	Removal of the Integrated Drive Generator - IDG 1(2)
AMM 24-21-51-400-040	Installation of the Integrated Drive Generator - IDG 1(2)
AMM 24-21-51-400-803	Installation of the Integrated Drive Generator - IDG 1(2)
AMM 24-22-34-000-001	Removal of the GCU-1(2)
AMM 24-22-34-400-001	Installation of the GCU-1(2)
AMM 24-41-00-740-002	Operational Check of the GAPCU via the CFDS
AMM 24-41-00-740-004	Operational Check of the GPCU via the CFDS
AMM 24-41-00-861-002	Energize the Aircraft Electrical Circuits from the External Power
AMM 24-41-00-862-002	De-energize the Aircraft Electrical Circuits Supplied from the External Power
AMM 31-60-00-860-001	EIS Start Procedure
AMM 31-60-00-860-002	EIS Stop Procedure
AMM 71-00-00-710-003	Engine Automatic Start
AMM 71-00-00-710-028	Engine Shutdown
AMM 71-00-00-860-814	Shutdown of the Engine
AMM 71-00-00-860-823	Start the Engine (Normal Automatic Start)

3. Fault Confirmation
Subtask 24-21-00-869-062-A

A. Test
(1) Not applicable

4. Fault Isolation
Subtask 24-21-00-810-099-A ** ON A/C NOT FOR ALL

A. If the fault symptom is identified by the CFDS message CHECK GCU 1 PIN B 14A, B14B IDG 1 PIN B1, B2 WIRING and the upper ECAM DU warning GEN 1 FAULT or if there is no connection of IDG 1 after engine start:

NOTE: After an automatic or manual disconnection of the IDG 1, do a GCU1 reset at first engine start. In this case, this trouble shooting procedure is not applicable

do a check of the wiring between the GCU 1 pins B/14A, B/14B and the IDG 1 pins B/1 and B/2 ASM 242101.

(1) If the wiring is not correct:

repair it.

(2) If the wiring is correct:

do a check of the resistance of the IDG 1 MPU coil between pin B/1 and pin B/2 (17.5 Ohms plus or minus 3.5 Ohms at 25 deg.C).

(a) If the resistance is out of the specified limits:

replace the IDG [4000XU] AMM 24-21-51-000-040 and AMM 24-21-51-400-040.

(b) If the resistance is in the specified limits:

replace the GCU-1 [1XU1] AMM 24-22-34-000-001 and AMM 24-22-34-400-001.

NOTE: Do not remove the GCU 1 before you do the other steps of the trouble shooting.

Subtask 24-21-00-860-076-A ** ON A/C NOT FOR ALL

B. Do this operational test to make sure that the system operates correctly.
(1) Aircraft Maintenance Configuration
(a) Energize the aircraft electrical circuits
AMM 24-41-00-861-002.
(b) Do the EIS start procedure (Upper ECAM DU and lower ECAM DU only)
AMM 31-60-00-860-001.
(2) On the ELEC panel 35VU:

push, release and push again the GEN 1 pushbutton switch (3XU1).

(3) Do the operational check of the GPCU with the CFDS AMM 24-41-00-740-004.
(4) Start the engine 1 AMM 71-00-00-710-003.

Subtask 24-21-00-810-099-E ** ON A/C NOT FOR ALL

C. If there is no connection of the IDG 1 after engine start:

NOTE: After an automatic or manual disconnection of the IDG 1, do a GCU1 reset at first engine start. In this case, this trouble shooting procedure is not applicable

(1) Replace IDG-ENG 1 [4000XU1] AMM 24-21-51-000-803 and AMM 24-21-51-400-803.

Subtask 24-21-00-860-076-F ** ON A/C NOT FOR ALL

D. Do this operational test to make sure that the system operates correctly.
(1) Aircraft Maintenance Configuration
(a) Energize the aircraft electrical circuits
AMM 24-41-00-861-002.
(b) Do the EIS start procedure (Upper ECAM DU and lower ECAM DU only)
AMM 31-60-00-860-001.
(2) In the cockpit, on the ELEC panel 35VU:

Push, release and push again the GEN 1 pushbutton switch (3XU1).

(3) Do the operational check of the GAPCU via the CFDS AMM 24-41-00-740-002.
(4) Start engine 1 AMM 71-00-00-860-823.

Subtask 24-21-00-810-099-H ** ON A/C NOT FOR ALL

E. If there is no connection of the IDG 1 after engine start:

NOTE: After an automatic or manual disconnection of the IDG 1, do a GCU1 reset at first engine start. In this case, this trouble shooting procedure is not applicable

(1) Replace the IDG [4000XU] AMM 24-21-51-000-040 and AMM 24-21-51-400-040.

Subtask 24-21-00-860-076-D ** ON A/C NOT FOR ALL

F. Do this operational test to make sure that the system operates correctly.
(1) Aircraft Maintenance Configuration
(a) Energize the aircraft electrical circuits
AMM 24-41-00-861-002.
(b) Do the EIS start procedure (Upper ECAM DU and lower ECAM DU only)
AMM 31-60-00-860-001.
(2) On the ELEC panel 35VU:

push, release and push again the GEN 1 pushbutton switch (3XU1).

(3) Do the operational test of the GAPCU AMM 24-41-00-740-002.
(4) Start the engine 1 AMM 71-00-00-710-003.

Subtask 24-21-00-710-091-A

G. Do this test:

ACTION	RESULT
On the ECAM control panel: get the ELEC page.	On the lower ECAM display unit: the correct electrical parameters of GEN 1 are shown and AC 1 busbar is supplied by GEN 1.

5. Close-up
Subtask 24-21-00-860-077-A ** ON A/C NOT FOR ALL

A. Put the aircraft back to its initial configuration.
(1) Stop the engine 1 AMM 71-00-00-710-028.
(2) Do the EIS stop procedure AMM 31-60-00-860-002.
(3) De-energize the aircraft electrical circuits
AMM 24-41-00-862-002.

Subtask 24-21-00-860-077-D ** ON A/C NOT FOR ALL

A. Put the aircraft back to its initial configuration.
(1) Stop engine 1 AMM 71-00-00-860-814.
(2) Do the EIS stop procedure AMM 31-60-00-860-002.
(3) De-energize the aircraft electrical circuits
AMM 24-41-00-862-002.

[Rev.8 from Aug 2018] 2026.04.04 04:26:33 UTC