Intermittent Failure of the ADF1

TASK 34-53-00-810-832-A
Intermittent Failure of the ADF1

1. Possible Causes

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
ASM 345301
AMM 34-53-11-000-001	Removal of the ADF Loop and Sense Antenna
AMM 34-53-11-400-001	Installation of the ADF Loop and Sense Antenna
AMM 34-53-31-000-002	Removal of the ADF Receiver
AMM 34-53-31-400-002	Installation of the ADF Receiver

3. Fault Confirmation
Subtask 34-53-00-700-050-A

A. Test
Not applicable, you cannot confirm this fault on the ground.

4. Fault Isolation
Subtask 34-53-00-810-093-A ** ON A/C NOT FOR ALL

A. If the fault symptom is identified by the crew observation ADF-incorrect ADF1 data shown on the NDs:

remove the RECEIVER-ADF, 1 [2RP1] AMM 34-53-31-000-002
do a check of the resistance between pins 7D and 8D on the plug of the rack connector
ASM 345301.

(1) If the resistance value is more than 6 ohms:

replace the ANTENNA-ADF LOOP AND SENSE, 1 [3RP1] AMM 34-53-11-000-001 AMM 34-53-11-400-001
install the RECEIVER-ADF, 1 [2RP1] AMM 34-53-31-400-002.

(2) If the resistance value is less than or equal to 6 ohms:

do a check of the resistance between pins 14D and 15D on the plug of the rack connector.

(a) If the resistance value is more than 6 ohms:

(3) If the fault continues:

remove the RECEIVER-ADF, 1 [2RP1] AMM 34-53-31-000-002
Make sure that all the electrical connections are clean and in the correct condition.
do a check and repair if necessary the wiring of the QEC STRAPPING of the RECEIVER-ADF, 1 [2RP1] ASM 345301.
install the RECEIVER-ADF, 1 [2RP1] AMM 34-53-31-400-002.

Subtask 34-53-00-810-093-C ** ON A/C NOT FOR ALL

A. If the fault symptom is identified by the crew observation ADF-incorrect ADF1 data shown on the NDs and on the VOR/ADF/DME RMI:

remove the RECEIVER-ADF, 1 [2RP1] AMM 34-53-31-000-002
do a check of the resistance between pins 7D and 8D on the plug of the rack connector
ASM 345301.

(1) If the resistance value is more than 6 ohms:

replace the ANTENNA-ADF LOOP AND SENSE, 1 [3RP1] AMM 34-53-11-000-001 AMM 34-53-11-400-001
install the RECEIVER-ADF, 1 [2RP1] AMM 34-53-31-000-002.

(2) If the resistance value is less than or equal to 6 ohms:

do a check of the resistance between pins 14D and 15D on the plug of the rack connector.

(a) If the resistance value is more than 6 ohms:

(3) If the fault continues:

remove the RECEIVER-ADF, 1 [2RP1] AMM 34-53-31-000-002
Make sure that all the electrical connections are clean and in the correct condition.
do a check and repair if necessary the wiring of the QEC STRAPPING of the RECEIVER-ADF, 1 [2RP1] ASM 345301.
install the RECEIVER-ADF, 1 [2RP1] AMM 34-53-31-400-002.

[Rev.8 from Aug 2018] 2026.04.04 04:33:29 UTC