Switching of the VDR3 to DATA Mode not Possible

TASK 46-21-00-810-840-A
Switching of the VDR3 to DATA Mode not Possible

1. Possible Causes

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
AMM 23-12-33-000-001	Removal of the VHF Transceiver
AMM 23-12-33-400-001	Installation of the VHF Transceiver
AMM 46-21-00-710-001	Operational Test of the ATSU
ASM 462104
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 46-21-00-740-126-A

A. Test
(1) Do the third part of the operational test of the ATSU AMM 46-21-00-710-001.

4. Fault Isolation
Subtask 46-21-00-810-088-A

A. If the VHF3 cannot operate in DATA mode during the operational test of the ATSU:

(1) If the fault continues:

(a) If the fault continues:

do a check and repair the wiring of the VOICE/DATA SELECT discrete from the ATSU (1TX1) pin AA/12A to the VDR3 (1RC3) pin AB/7C ASM 462104.

Subtask 46-21-00-740-127-A

B. Do the test given in Para. 3.

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