F/O Electrical System Panel, P6-1
Row Col Number Name
A 13 C01480 RADIO NAVIGATION MMR 2

D. Related Data
(1)
(SSM 34-31-11).

(2)
(SSM 34-31-21).

(3)
(WDM 34-31-11).

(4)
(WDM 34-31-21).

E. Initial Evaluation
(1) Do
this
task:
ILS
or
Multi-Mode
Receiver
BITE
Procedure,
34-31
TASK
801.

(a)
If the maintenance message shows, then do the Fault Isolation Procedure below.

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

EFFECTIVITY

34-31 TASKS 815-816
SIL ALL
Page 224 D633A103-SIL Feb 15/2010

F. Fault Isolation Procedure
(1)
Replace the applicable LOC antenna switch, R315 or R316.
These are the tasks:
Localizer Antenna Switch Removal, AMM TASK 34-31-72-000-801,
Localizer Antenna Switch Installation, AMM TASK 34-31-72-400-801.

(a)  
Do
this
task:
ILS
or
Multi-Mode
Receiver
BITE
Procedure,
34-31
TASK
801.

(b)  
If the LCD display on the multi-mode receiver shows ILS TEST COMPLETE NO FAILURES, then you corrected the fault.

(c)  
If the multi-mode receiver LCD display shows LOC ANTENNA FAILED, then continue.

(2)  
Do this check of the wiring:

(a)  
Remove the multi-mode receiver. To remove it, do this task: Receiver for ILS -Removal, AMM TASK 34-31-42-000-801.

(b)  
Disconnect the applicable connector from the applicable LOC antenna switch.

(c)  
Do a continuity check between the multi-mode receiver and the applicable LOC antenna switch:

SWITCH MMR CONNECTOR CONNECTOR SWITCH 1 (R315) D2115 D10719C
pinA1 ------------------pin12 pinC1 ------------------pinC12

SWITCH 2 (R316) D2123  D10721C
pinA1 ------------------pin12 pinC1 ------------------pinC12

(d)  If there is not continuity, then do these steps: 1) Repair the wiring. 2) Re-connect the applicable connector. 3) Re-install the multi-mode receiver. To install it, do this task: Receiver for ILS -
Installation, AMM TASK 34-31-42-400-801. 4) Do
this
task:
ILS
or
Multi-Mode
Receiver
BITE
Procedure,
34-31
TASK
801.
5) If the LCD display on the multi-mode receiver shows MMR TEST COMPLETE NO
FAILURES, then you corrected the fault.
(e)  If there is continuity, then continue.
(3)  Use a time domain reflectometer (TDR) test set time domain reflectometer, COM-5187to do an electrical check of the coaxial cable and antenna:
CAUTION:  YOU MUST PUT RF ABSORBENT MATERIAL ON THE ANTENNA BEFORE YOU USE THE TDR TEST SET. YOU CAN DAMAGE THE TEST SET IF A HIGH POWER TRANSMITTER OPERATES WITHIN 500 FEET OF THE ANTENNA.
(a)  
Cover the ILS localizer antenna, M1102 with RF absorbent material.

(b)  
Disconnect connector D2117 from the ILS localizer antenna switch-1, R315 or connector D2125 from the ILS localizer antenna switch-2, P316 as applicable.

(c)  
Connect the TDR test set time domain reflectometer, COM-5187at pins A1 and C1 of the applicable connector at the ILS localizer antenna switch.

(d)  
Do an electrical check of the coaxial cable and the antenna.

NOTE: The TDR test set has instructions which tell how to do the check of the cable and antenna.

(e)  
Disconnect the TDR test settime domain reflectometer, COM-5187.

(f)  
Re-connect connector D2117 or D2125 as applicable.

(g)  
If you find a problem with the coaxial cable, then do these steps: 1) Replace the coaxial cable. 2) Do
　
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