Failure of the DME Interrogator 1

TASK 34-51-00-810-801-A
Failure of the DME Interrogator 1

1. Possible Causes

INTRG-DME, 1 [2SD1]
short to ground at the wiring between the circuit breaker (1SD1) and the DME receiver 1 (2SD1)
C/B-NAV/DME/1 [1SD1]

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
AMM 34-51-00-740-002	BITE Test of the DME
ASM 345101
AMM 34-51-33-000-001	Removal of the DME Interrogator
AMM 34-51-33-400-001	Installation of the DME Interrogator

3. Fault Confirmation
Subtask 34-51-00-865-058-A

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

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C ALL
49VU	NAV/DME/1	1SD1	G14

Subtask 34-51-00-740-050-A

B. Test
(1) If the circuit breaker (1SD1) trips, refer to Para. 4. C. of this trouble shooting procedure.
(2) Do the BITE test of the DME AMM 34-51-00-740-002.

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

4. Fault Isolation
Subtask 34-51-00-810-050-B

A. If the circuit breaker (1SD1) is closed, and if the BITE test gives the maintenance message DME1 (2SD1):

replace the INTRG-DME, 1 [2SD1] AMM 34-51-33-000-001 and AMM 34-51-33-400-001.

Subtask 34-51-00-810-051-A

B. If the circuit breaker (1SD1) is closed and if the BITE test is not possible

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

(1) If there is no 115VAC:

do a check of the wiring of the 115VAC signal from circuit breaker (1SD1) to DME receiver 1 (2SD1) ASM 345101.

(a) If there is no continuity:

repair the above wiring.

(b) If there is continuity:

replace the C/B-NAV/DME1 (1SD1).

(2) If there is 115VAC:

do a check of the wiring of the ground signal at DME receiver 1 pin AC/7.

(a) If there is no continuity:

repair the above wiring.

Subtask 34-51-00-810-078-A

C. If the circuit breaker (1SD1) is open:

close this circuit breaker.

(1) If the circuit breaker (1SD1) trips:

remove the INTRG-DME, 1 [2SD1] AMM 34-51-33-000-001.
close the circuit breaker (1SD1).

(a) If this circuit breaker stays closed:

install the DME receiver 1 AMM 34-51-33-400-001

1 If the circuit breaker trips again:

replace the DME receiver 1 AMM 34-51-33-000-001 and AMM 34-51-33-400-001.

(b) If this circuit breaker trips again:

do a check for a short to ground at the wiring between the circuit breaker (1SD1) and the DME receiver 1 (2SD1) ASM 345101.

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/DME/1 [1SD1] .

3 Install the DME receiver 1
AMM 34-51-33-400-001.

Subtask 34-51-00-740-051-A

D. Do the test given in Para. 3.

[Rev.8 from Aug 2018] 2026.04.04 04:33:18 UTC