Loss of the Weather Radar Picture detected by DMC 2 when the ND is shown on the F/O ND DU

TASK 31-63-81-810-899-A
Loss of the Weather Radar Picture detected by DMC 2 when the ND is shown on the F/O ND DU

1. Possible Causes

DMC-2 [1WT2]
ND-F/O [3WT2]
XCVR-WEATHER RADAR, 1 [1SQ1]
wiring

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
AMM 24-41-00-861-002	Energize the Aircraft Electrical Circuits from the External Power
AMM 24-41-00-862-002	De-energize the Aircraft Electrical Circuits Supplied from the External Power
AMM 31-60-00-740-004	EIS System Test
ASM 316100
ASM 316200
AMM 31-63-22-000-001	Removal of the Display Unit
AMM 31-63-22-400-001	Installation of the Display Unit
AMM 31-63-34-000-001	Removal of the DMC
AMM 31-63-34-400-001	Installation of the DMC
AMM 34-10-00-860-002	ADIRS Start Procedure
AMM 34-10-00-860-005	ADIRS Stop Procedure
ASM 344100
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

WARNING: MAKE SURE THAT:

NO PERSON IS IN THE AREA MADE BY AN ARC OF 135° ON EACH SIDE OF THE AIRCRAFT CENTERLINE. -THERE IS A MINIMUM SAFETY DISTANCE OF 5 METERS (16.4FT) BETWEEN THE AIRCRAFT AND ANY OBSTACLE IN THE AREA MADE BY AN ARC OF 90° ON EACH SIDE OF THE AIRCRAFT CENTERLINE.

Subtask 31-63-81-860-070-A ** ON A/C NOT FOR ALL

A. Aircraft Maintenance Configuration
(1) Energize the aircraft electrical circuits
AMM 24-41-00-861-002
(2) Do the ADIRS start procedure AMM 34-10-00-860-002
(3) On the EFIS control panel of the FCU:

set the mode selector switches to ARC

(4) on the center pedestal, on the WEATHER RADAR CONTROL-UNIT (3SQ), start the weather radar system.
(5) On the FO EFIS switching panel 500VU:

make sure that the FO ND potentiometer (8WT2) is in the center position.

Subtask 31-63-81-865-063-A ** ON A/C NOT FOR ALL

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

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
121VU	COM NAV/RADAR/1	5SQ1	K13

Subtask 31-63-81-740-244-A ** ON A/C NOT FOR ALL

C. Test
Do the EIS system test AMM 31-60-00-740-004

Subtask 31-63-81-860-071-A ** ON A/C NOT FOR ALL

D. Put the aircraft back to its initial configuration.
(1) Do the ADIRS stop procedure AMM 34-10-00-860-005
(2) De-energize the aircraft electrical circuits
AMM 24-41-00-862-002

4. Fault Isolation
Subtask 31-63-81-810-165-A ** ON A/C NOT FOR ALL

A. If the test gives the maintenance message WXR1(1SQ1)/DU ND FO(3WT2)/DMC2 (1WT2):

replace the DMC-2 [1WT2] AMM 31-63-34-000-001 AMM 31-63-34-400-001

(1) If the fault continues:

replace the ND-F/O [3WT2] AMM 31-63-22-000-001 AMM 31-63-22-400-001

(2) If the fault continues:

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

(3) If the fault continues:

remove the DMC2 (1WT2) AMM 31-63-34-000-001
remove the FO ND DU (3WT2) AMM 31-63-22-000-001
remove the WEATHER RADAR-XCVR1 (1SQ1) AMM 34-41-33-000-004

(a) Check the wiring of the WXR1 OUTPUT BUS from the DMC2 (1WT2) pins AB/14B, 14C to the FO ND DU (3WT2) ASM 316100
(b) Check the wiring between the DMC2 (1WT2) and the WEATHER RADAR-XCVR 1 (1SQ1) ASM 316200 ASM 344100

install the DMC2 (1WT2) AMM 31-63-34-400-001
install the FO ND DU (3WT2) AMM 31-63-22-400-001
install the WEATHER RADAR-XCVR1 (1SQ1) AMM 34-41-33-400-003

Subtask 31-63-81-740-245-A ** ON A/C NOT FOR ALL

B. Do the test given in Para. 3.A.

[Rev.8 from Aug 2018] 2026.04.04 04:31:02 UTC