Failure of the ADF Receiver 2

TASK 34-53-00-810-802-A
Failure of the ADF Receiver 2

1. Possible Causes

RECEIVER-ADF, 2 [2RP2]
wiring from the ADF antenna 2 (3RP2) to the ADF receiver 2 (2RP2)
ANTENNA-ADF LOOP AND SENSE, 2 [3RP2]
short to ground at the wiring between the circuit breaker (1RP2) and the ADF receiver 2 (2RP2)
C/B-DUMMY CB or C/B-COM NAV/ADF/2 [1RP2]

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
AMM 34-53-00-740-003	BITE Test of the ADF
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 34-53-00-865-069-A ** ON A/C NOT FOR ALL

A. Make sure that this(these) circuit breaker(s) is(are) closed:

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
121VU	COM NAV/ADF/2	1RP2	K02

Subtask 34-53-00-740-052-A ** ON A/C NOT FOR ALL

B. Test
(1) If the circuit breaker (1RP2) trips, refer to Para. 4. C. of this trouble shooting procedure.
(2) Do the BITE test of the ADF AMM 34-53-00-740-003.

If the BITE test is not possible, refer to Para. 4. B. of this trouble shooting procedure.

4. Fault Isolation
Subtask 34-53-00-810-099-B ** ON A/C NOT FOR ALL

A. If the circuit breaker (1RP2) is closed, and if the BITE test gives the maintenance message ADF2 (2RP2):

replace the RECEIVER-ADF, 2 [2RP2] AMM 34-53-31-000-002 and AMM 34-53-31-400-002.

(1) If the fault continues:

do a check of the wiring from the ADF antenna 2 (3RP2) to the ADF receiver 2 (2RP2) ASM 345301.

(a) If there is no continuity:

repair the above wiring.

(b) If there is continuity:

repair the ANTENNA-ADF LOOP AND SENSE, 2 [3RP2] AMM 34-53-11-000-001 and AMM 34-53-11-400-001.

Subtask 34-53-00-810-053-A ** ON A/C NOT FOR ALL

B. If the circuit breaker (1RP2) is closed and if the BITE test is not possible:

do a check for 115VAC at pin AC/2 of the ADF receiver 2.

(1) If there is no 115VAC:

do a check of the wiring of the 115VAC signal from circuit breaker (1RP1) to ADF receiver 2 (2RP2) ASM 345301.

(a) If there is no continuity:

repair the above wiring.

(b) If there is continuity:

replace the C/B-NAV/ADF/2 (1RP2).

(2) If there is 115VAC:

do a check of the wiring of the ground signal at ADF receiver 2 pin AC/4.

(a) If there is no continuity:

repair the above wiring.

Subtask 34-53-00-810-079-A ** ON A/C NOT FOR ALL

C. If the circuit breaker (1RP2) is open:

close this circuit breaker.

(1) If the circuit breaker (1RP2) trips:

remove the RECEIVER-ADF, 2 [2RP2] AMM 34-53-31-000-002.
close the circuit breaker (1RP2).

(a) If this circuit breaker stays closed:

install the ADF receiver 2 AMM 34-53-31-400-002

1 If the circuit breaker trips again:

replace the ADF receiver 2 AMM 34-53-31-000-002 and AMM 34-53-31-400-002.

(b) If this circuit breaker trips again:

do a check for a short to ground at the wiring between the circuit breaker (1RP2) and the ADF receiver 2 (2RP2) ASM 345301.

1 If there is a short to ground:

repair the above wiring.

2 If there is no short to ground:

replace the C/B-DUMMY CB or C/B-COM NAV/ADF/2 [1RP2] .

3 Install the ADF receiver 2
AMM 34-53-31-400-002.

Subtask 34-53-00-740-053-A ** ON A/C NOT FOR ALL

D. Do the test given in Para. 3.

[Rev.8 from Aug 2018] 2026.04.04 04:33:26 UTC