Loss of the Clock Data Detected by the ATSU

TASK 46-21-00-810-806-A
Loss of the Clock Data Detected by the ATSU

1. Possible Causes

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
AMM 31-21-21-000-001	Removal of the Clock
AMM 31-21-21-400-001	Installation of the Clock
AMM 46-21-00-740-001	BITE Test of the ATIMS
ASM 462105
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 46-21-00-740-060-A

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

4. Fault Isolation
Subtask 46-21-00-810-055-A

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

(1) If the fault continues:

(a) If the fault continues:

remove the clock and the ATSU
do a check and repair the wiring of the ATA 31 CLOCK INPUT BUS : between pins A/W,X of the clock and pins AA/5J,5K of the ATSU ASM 462105
install the clock and the ATSU.

Subtask 46-21-00-740-061-A

B. Do the test given in Para. 3.

[Rev.8 from Aug 2018] 2026.04.04 04:34:18 UTC