Failure of the Weather Radar Transceiver 1

TASK 34-41-00-810-802-A
Failure of the Weather Radar Transceiver 1

1. Possible Causes

XCVR-WEATHER RADAR, 1 [1SQ1]
wave guide switch
short to ground at the wiring between the circuit breaker (5SQ1) and the weather radar transceiver 1 (1SQ1).
C/B-COM NAV/RADAR/1

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
AMM 34-41-00-730-001	System Test of the Weather Radar
AMM 34-41-00-740-002	BITE Test of the Weather Radar
ASM 344101
AMM 34-41-33-000-004	Removal of the Weather Radar Transceiver
AMM 34-41-33-400-003	Installation of the Weather Radar Transceiver

3. Fault Confirmation
Subtask 34-41-00-865-050-A

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

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C ALL
121VU	COM NAV/RADAR/1	5SQ1	K13

Subtask 34-41-00-740-050-A

B. Test
(1) If the circuit breaker (5SQ1) trips, refer to Para. 4. D. of this trouble shooting procedure.
(2) Do the BITE test of the weather radar AMM 34-41-00-740-002.

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

4. Fault Isolation
Subtask 34-41-00-810-052-A ** ON A/C NOT FOR ALL

A. If the circuit breaker (5SQ1) is closed, and if the BITE test gives the maintenance message RADAR1 TRANSCEIVER:

if the weather-radar mounting tray has an internal filter, do a check and/or clean it (refer to the CMM equipment specifications).

(1) If the fault continues:

replace the XCVR-WEATHER RADAR, 1 [1SQ1] AMM 34-41-33-000-004 and AMM 34-41-33-400-003.

Subtask 34-41-00-810-052-B ** ON A/C NOT FOR ALL

A. If the circuit breaker (5SQ1) is closed, and if the BITE test gives the maintenance message WXR1 (1SQ1):

replace the XCVR-WEATHER RADAR, 1 [1SQ1] AMM 34-41-33-000-004 and AMM 34-41-33-400-003.

Subtask 34-41-00-810-092-A

B. If the circuit breaker (5SQ1) is closed, and if the BITE test is OK:

do a system test of the weather radar 1 AMM 34-41-00-730-001:
If the system test is OK, no maintenance action is necessary.
If the system test confirms the weather radar fault, replace the wave guide switch .

Subtask 34-41-00-810-053-A

C. If the circuit breaker (5SQ1) is closed and if the BITE test is not possible

do a check for 115VAC at pin AC/2 of the weather radar transceiver 1.

(1) If there is no 115VAC:

do a check of the wiring of the 115VAC signal from circuit breaker (5SQ1) to weather radar transceiver 1 (1SQ1) ASM 344101.

(a) If there is no continuity:

repair the above wiring.

(b) If there is continuity:

replace the C/B-COM NAV/RADAR/1 (5SQ1).

(2) If there is 115VAC:

do a check of the wiring of the ground signal at weather radar transceiver 1 pin AC/7.

(a) If there is no continuity:

repair the above wiring.

Subtask 34-41-00-810-081-A

D. If the circuit breaker (5SQ1) is open:

close this circuit breaker.

(1) If the circuit breaker (5SQ1) trips:

remove the XCVR-WEATHER RADAR, 1 [1SQ1] AMM 34-41-33-000-004.
close the circuit breaker (5SQ1).

(a) If this circuit breaker stays closed:

install the weather radar transceiver 1 AMM 34-41-33-400-003.

1 If the circuit breaker trips again:

replace the weather radar transceiver 1 AMM 34-41-33-000-004 and AMM 34-41-33-400-003.

(b) If this circuit breaker trips again:

do a check for a short to ground at the wiring between the circuit breaker (5SQ1) and the weather radar transceiver 1 (1SQ1). ASM 344101.

1 If there is a short to ground:

repair the above wiring.

2 If there is no short to ground:

replace the C/B-COM NAV/RADAR/1.

3 Install the weather radar transceiver 1 AMM 34-41-33-400-003.

Subtask 34-41-00-740-051-A

E. Do the test given in Para. 3.

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