Failure of the ADF Receiver 1

TASK 34-53-00-810-801-A
Failure of the ADF Receiver 1

1. Possible Causes

RECEIVER-ADF, 1 [2RP1]
wiring from the ADF antenna 1 (3RP1) to the ADF receiver 1 (2RP1)
ANTENNA-ADF LOOP AND SENSE, 1 [3RP1]
short to ground at the wiring between the circuit breaker (1RP1) and the ADF receiver 1 (2RP1)
C/B-NAV/ADF/1 [1RP1]

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 34-53-00-865-058-A

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

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
49VU	NAV/ADF/1	1RP1	H14
** ON A/C NOT FOR ALL
49VU	NAV/ADF/1	1RP1	F09

Subtask 34-53-00-740-050-A

B. Test
(1) If the circuit breaker (1RP1) 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 34-53-00-810-098-B

A. If the circuit breaker (1RP1) is closed, and if the BITE test gives the maintenance message ADF1 (2RP1):

replace the RECEIVER-ADF, 1 [2RP1] 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 1 (3RP1) to the ADF receiver 1 (2RP1) ASM 345301.

(a) If there is no continuity:

repair the above wiring.

(b) If there is continuity:

repair the ANTENNA-ADF LOOP AND SENSE, 1 [3RP1] AMM 34-53-11-000-001 and AMM 34-53-11-400-001.

Subtask 34-53-00-810-051-A

B. If the circuit breaker (1RP1) is closed and if the BITE test is not possible

do a check for 115VAC at pin AC/2 of the ADF receiver 1.

(1) If there is no 115VAC:

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

(a) If there is no continuity:

repair the above wiring.

(b) If there is continuity:

replace the C/B-NAV/ADF/1 (1RP1).

(2) If there is 115VAC:

do a check of the wiring of the ground signal at ADF receiver 1 pin AC/4.

(a) If there is no continuity:

repair the above wiring.

Subtask 34-53-00-810-078-A

C. If the circuit breaker (1RP1) is open:

close this circuit breaker.

(1) If the circuit breaker (1RP1) trips:

remove the RECEIVER-ADF, 1 [2RP1] AMM 34-53-31-000-002.
close the circuit breaker (1RP1).

(a) If this circuit breaker stays closed:

install the ADF receiver 1 AMM 34-53-31-400-002

1 If the circuit breaker trips again:

replace the ADF receiver 1 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 (1RP1) and the ADF receiver 1 (2RP1) 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-NAV/ADF/1 [1RP1] .

3 Install the ADF receiver 1
AMM 34-53-31-400-002.

Subtask 34-53-00-740-051-A

D. Do the test given in Para. 3.

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