Overcurrent on the GEN 1 Because of a Failure of the BTC 1 Status Circuit

TASK 24-20-00-810-890-A
Overcurrent on the GEN 1 Because of a Failure of the BTC 1 Status Circuit

1. Possible Causes

GCU-1 [1XU1]
wiring
BTC-1 [11XU1]

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
TSM TASK 24-20-00-810-918-A	Overload on the Electrical Network of the Generator 1
ASM 242202
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 24-22-55-000-001	Removal of the Contactors
AMM 24-22-55-400-002	Installation of the Contactors
AMM 24-41-00-740-002	Operational Check of the GAPCU via the CFDS

3. Fault Confirmation
Subtask 24-20-00-740-088-A ** ON A/C NOT FOR ALL

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

NOTE: If the CFDS message GEN1 OVERCURRENT + GCU1 (1XU1)/ BTC1 (11XU1) comes into view, do the trouble shooting for an IDG 1 overcurrent condition with the procedure (Ref. TSM TASK 24-20-00-810-918).

(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 24-20-00-810-185-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 GCU1 (1XU1) comes into view:

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

Subtask 24-20-00-810-186-A ** ON A/C NOT FOR ALL

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

do a check of the coil return wiring for a short circuit or a short to ground between pin B/5 of the BTC 1 and pin A/9A of the GCU 1 ASM 242202.

(1) If the wiring is not correct:

repair or replace as necessary.

(2) If the wiring is correct:

do a check of the BTC 1 auxiliary contact for correct operation between pin B/27 and pin B/29 ASM 242202.

(a) If there is no continuity:

replace the BTC-1 [11XU1] AMM 24-22-55-000-001 and AMM 24-22-55-400-002.

(b) If there is continuity:

do a check of the wiring for a short circuit or a short to ground between pin B/29 of the BTC 1 and pin A/4C of the GCU 1 ASM 242202.

1 If the wiring is not correct:

repair or replace as necessary.

2 If the wiring is correct:

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

Subtask 24-20-00-740-089-A ** ON A/C NOT FOR ALL

C. Do the test given in Para. 3.

[Rev.8 from Aug 2018] 2026.04.04 04:26:19 UTC