FAILURES, then you corrected the fault.

(h)  
If you find a problem with the antenna, then do these steps:

EFFECTIVITY SIL ALL  34-31 TASK 816 
D633A103-SIL BOEING PROPRIETARY -Copyright # Unpublished Work -See title page for details  Page 225 Feb 15/2010 

1) Replace the ILS LOC antenna, M1102. These are the tasks: Localizer Antenna Removal, AMM TASK 34-31-31-000-801, Localizer Antenna Installation, AMM TASK 34-31-31-400-801.
2) Do
this
task:
ILS
or
Multi-Mode
Receiver
BITE
Procedure,
34-31
TASK
801.
3) If the LCD display on the multi-mode receiver shows MMR TEST COMPLETE NO FAILURES, then you corrected the fault.
-------------------------END OF TASK ---------------------------
817.  ILS GS Antenna Failed -Fault Isolation
A. Description
(1)
The task is for this maintenance message:

(a)  GS ANTENNA FAILED

(2)
Multi-mode receiver receives no input signal from the glideslope (GS) antenna, M40.

B. Possible Causes
(1)
Wiring problem.

(2)
GS antenna, M40.

C. Circuit Breakers
(1) These are the primary circuit breakers related to the fault:
CAPT Electrical System Panel, P18-1
Row Col Number Name
A 2 C01479 RADIO NAVIGATION MMR 1

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

EFFECTIVITY

34-31 TASKS 816-817
SIL ALL
Page 226 D633A103-SIL Feb 15/2010

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

F. Fault Isolation Procedure
(1) Use a time domain reflectometer (TDR) test set to 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 left ILS GS antenna, M40 with RF absorbent material.

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

(c)  
Connect the TDR test set at pins 13 and C13 of connector D10719C or pins 12 and C12 of connector D10721C as applicable at the multi-mode receiver.

(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 set.

(f)  
Re-install the multi-mode receiver. To install it, do this task: Receiver for ILS -Installation, AMM TASK 34-31-42-400-801.

(g)  
If you find a problem with the coaxial cable, then do these steps: 1) Replace the coaxial cable. 2) Do
this
task:
ILS
or
Multi-Mode
Receiver
BITE
Procedure,
34-31
TASK
801.
3) If the LCD display on the multi-mode receiver shows MMR TEST COMPLETE NO
　
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