D.  Related Data
(1)
(SSM 34-21-11)

(2)
(WDM 34-21-11)

E.  Initial Evaluation
(1)
For
the
applicable
ADIRS,
do
this
task:
ADIRS
BITE
Procedure,
34-21
TASK
801.

(2)  
If the maintenance message does not show on the CDU, then there was an intermittent fault.

(3)  
If the maintenance message shows on the CDU, then do the Fault Isolation Procedure below.

EFFECTIVITY SIL ALL  34-21 TASK 802 
D633A103-SIL BOEING PROPRIETARY -Copyright # Unpublished Work -See title page for details  Page 205 Oct 15/2008 

F.  Fault Isolation Procedure
(1)
Replace the ISDU.
These are the tasks:
Inertial System Display Unit Removal, AMM TASK 34-21-02-000-801,
Inertial System Display Unit Installation, AMM TASK 34-21-02-400-801.

(a)  
Do a check for the bend pins at the connectors.

(b)  
For
the
applicable
ADIRS,
do
this
task:
ADIRS
BITE
Procedure,
34-21
TASK
801.
1) If the maintenance message does not show on the CDU, then you corrected the fault. 2) If the maintenance message shows on the CDU, then continue.

(2)  
Do this check of the wiring between the applicable ADIRU and the ISDU:

(a)  
Remove the ADIRU. To remove it, do this task: Air Data Inertial Reference Unit Removal, AMM TASK 34-21-01-000-801.

(b)  
Remove the ISDU. To remove it, do this task: Inertial System Display Unit Removal, AMM TASK 34-21-02-000-801.

(c)  
For the left ADIRU maintenance message, do a wiring check between these pins of connector D3687B for the ADIRU and connector D2169 for the ISDU:

D3687B  D2169
pinC5 ------------------pin24A pinC6 ------------------pin25B

(d)  For the right ADIRU maintenance message, do a wiring check between these pins of connector D3693B for the ADIRU and connector D2183 for the ISDU:
D3693B  D2183
pinC5 ------------------pin24A pinC6 ------------------pin25B

(e)  If you find a problem with the wiring, then do these steps: 1) Repair the wiring. 2) Re-install the ADIRU. To install it, do this task: Air Data Inertial Reference Unit
Installation, AMM TASK 34-21-01-400-801. 3) Re-install the ISDU. To install it, do this task: Inertial System Display Unit Installation,
AMM TASK 34-21-02-400-801. 4) For
the
applicable
ADIRS,
do
this
task:
ADIRS
BITE
Procedure,
34-21
TASK
801.
5) If the maintenance message does not show on the CDU, then you corrected the fault. 6) If the maintenance message does show on the CDU, then continue.
(f)  If you do not find a problem with the wiring, then do this step and continue.
1)  Re-install the ISDU. To install it, do this task: Inertial System Display Unit Installation, AMM TASK 34-21-02-400-801.
(3) Replace the ADIRU.
These are the tasks:
Air Data Inertial Reference Unit Removal, AMM TASK 34-21-01-000-801,
Air Data Inertial Reference Unit Installation, AMM TASK 34-21-01-400-801.

(a)  For
the
applicable
ADIRS,
do
this
task:
ADIRS
BITE
Procedure,
34-21
TASK
801.
1) If the maintenance message does not show on the CDU, then you corrected the fault.
EFFECTIVITY SIL ALL  34-21 TASK 802 
D633A103-SIL BOEING PROPRIETARY -Copyright # Unpublished Work -See title page for details  Page 206 Oct 15/2008 
　
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