Loss of the DCDU 1 Data detected by the ATSU

TASK 46-21-00-810-852-A
Loss of the DCDU 1 Data detected by the ATSU

1. Possible Causes

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
AMM 46-21-00-740-001	BITE Test of the ATIMS
ASM 462105
AMM 46-21-21-000-001	Removal of the Datalink Control and Display Unit (DCDU)
AMM 46-21-21-400-001	Installation of the Datalink Control and Display Unit (DCDU)
AMM 46-21-34-000-001	Removal of the Air Traffic Service Unit (ATSU)
AMM 46-21-34-400-001	Installation of the Air Traffic Service Unit (ATSU)

3. Fault Confirmation
Subtask 46-21-00-740-148-A ** ON A/C NOT FOR ALL

A. Test
(1) Do the BITE test of the ATIMS AMM 46-21-00-740-001.

4. Fault Isolation
Subtask 46-21-00-810-101-A ** ON A/C NOT FOR ALL

A. If the test gives the maintenance message DCDU1(2TX1)/ATSU1(1TX1):

(1) If the fault continues:

(a) If the fault continues:

remove the DCDU 1 and the ATSU
do a check and repair the wiring of the DCDU GEN/1 INPUT BUS between pins A/-H,-I of the DCDU 1 and pins AA/5E,5F of the ATSU ASM 462105.
install the DCDU 1 and the ATSU.

Subtask 46-21-00-740-149-A ** ON A/C NOT FOR ALL

B. Do the test given in Para. 3.

[Rev.8 from Aug 2018] 2026.04.04 04:34:21 UTC