Failure of the Disconnect Solenoid System of the IDG 2

TASK 24-21-00-810-821-A
Failure of the Disconnect Solenoid System of the IDG 2

1. Possible Causes

GCU-2 [1XU2]
IDG [4000XU]
RELAY-IDG 2 DISC CTL [4XT]
wiring
IDG-ENG 2 [4000XU2]

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
AMM 24-21-00-710-803	Operational Test of the IDG Disconnect and Reconnect (Reset) Function - Engine Static
AMM 24-21-00-720-041	Operational Test of the IDG Disconnect and Reconnect (Reset) Function - Engine in Operation
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

3. Fault Confirmation
Subtask 24-21-00-740-060-A ** ON A/C NOT FOR ALL

A. Test
(1) Do the BITE test of the GAPCU AMM 24-41-00-740-002.

NOTE: Do the trouble shooting for all the other CFDS messages related to the IDG 2 that come into view with the message IDG2 (E2-4000XU)/ RELAY (4XT)/GCU2 (1XU2).

(a) If the BITE test gives the message TEST FAILED:

do the trouble shooting given in Para 4.A.

(b) If the BITE test gives the message TEST PASSED:

do the trouble shooting given in Para 4.B.

4. Fault Isolation
Subtask 24-21-00-810-090-A ** ON A/C NOT FOR ALL

A. If the BITE test gives the message TEST FAILED:

push the line key adjacent to the TEST FAILED message.

(1) If the maintenance message GCU2 (1XU2) comes into view:

replace the GCU-2 [1XU2] AMM 24-22-34-000-001 and AMM 24-22-34-400-001.

Subtask 24-21-00-810-080-F ** ON A/C NOT FOR ALL

B. If the BITE test gives the message TEST PASSED:

do an electrical resistance test of the IDG 2 disconnect solenoid for an open circuit or a high resistance condition between pin A/12 and pin A/13 of the IDG 2 (3 ohms plus or minus 1 ohm) ASM 242101.

(1) If the resistance values are out of the specified limits:

replace the engine 2 IDG [4000XU] AMM 24-21-51-000-040 and AMM 24-21-51-400-040.

(2) If the resistance values are in the specified limits:

replace the RELAY-IDG 2 DISC CTL [4XT]
do a dynamic disconnect test of the IDG 2 AMM 24-21-00-720-041.

(a) If the test is OK:

stop the trouble shooting.

(b) If the test is not OK:

do a check of the wiring for an open circuit or a short to ground between pin A1 of the IDG 2 disconnect control relay (4XT) and pin A/12 of the IDG 2 ASM 242101.

1 If the wiring is not correct:

repair or replace as necessary.

2 If the wiring is correct:

replace the GCU-2 [1XU2] AMM 24-22-34-000-001 and AMM 24-22-34-400-001.

a If the fault continues:

replace the engine 2 IDG [4000XU] AMM 24-21-51-000-040 and AMM 24-21-51-400-040.

Subtask 24-21-00-810-080-J ** ON A/C NOT FOR ALL