D. Control
 (1)  
Prior to operating the marker beacon system, electrical power must be provided to the airplane (Ref 24-22-00, Maintenance Practices).

 (2)  
The master radio switches on pilots' overhead panel (P5) and the MKR BCN circuit breaker on P7 panel must be closed. The sensitivity switch should be set for maximum sensitivity.

 (3)  
The marker beacon system should be operational as evidenced by illumination of the marker beacon indicator lights when pressed.

 EFFECTIVITY

 
 ALL  01 Page 4  Sep 25/9434-32-00
......XA

(BLUE)
2
SN ONLY F/O'S MARKER LIGHT SET Marker Beacon System Block Diagram (PUSH-TO-TEST) Figure 2 (Sheet 1)
EFFECTIVITY AF 172-182,185-199; AT ALL; AZ ALL; GN ALL; LH ALL;
7XA Page 5
34-32-00
MD ALL; SN ALL; VM ALL Sep 25/94

 MARKER BEACON SYSTEM - TROUBLE SHOOTING
_______________________________________
 1.  General
_______
 A.  The following trouble shooting procedures are based on performance of the system operational test and are presented in tree-type format. The test steps (heavy-line boxes) are connected by shaded arrows to show the OK condition path. When all steps in the OK condition path check out, the system is operable.
 B.  When a test step does not check out, follow the NOT OK line to the box containing the trouble symptom. Turn to the procedure indicated and continue to follow a single line by analyzing the results of each test step until the required corrective action is determined. Perform the specified corrective action; then repeat the step at which the failure was encountered.
 C.  All trouble shooting procedures are based on the assumption that wiring is OK and electrical power is available. If the corrective action in the procedure does not correct the problem, check wiring using the wiring diagram.
 2.  Prepare for Trouble Shooting
____________________________
 A.  Provide electrical power (Ref 24-22-00, Maintenance Practices).
 B.  AF 121-122, 151-199; AT ALL;
 AZ ALL; LH ALL; GN ALL; MD ALL;
 SN ALL; VM ALL;
 Verify that MKR BCN circuit breaker on P7 panel is closed.

 C.  AF 101-120, 123-150; Verify that MKR BCN and MKR BCN-1 circuit breakers on P7 panel are closed.
 D.  AF 101-120, 123-150; Verify that standby ignition switch on P5 panel is in NORM position.
 E.  Verify that flight interphone system is operating correctly (Ref
 23-51-00, Adjustment/Test).

 (1)  Activate marker beacon audio selector control and adjust control for moderate volume.
 F.  LH 001-050; AF 101-120, 123-150; Set up marker beacon test set approximately 15 feet away from marker beacon antenna. Extend test set antenna and align parallel to fore and aft axis of airplane. Turn on test set and allow to warm up.
 EFFECTIVITY

 
 ALL  03 Page 101  Sep 25/9434-32-00
Prepare for troubleshooting as described in par. 2. Press each marker beacon indicator light on captain's and first officer's instrument panels. Check that each indicator light comes on when pressed. IF -

Press and hold test switch on front panel of marker beacon receiver for 5 seconds. Release switch. Check that marker beacon indicator lights on captain's and first officer's instrument panels come on in sequence (blue, amber and clear), and listen for sequence of 400-Hz, 1300-Hz, 3000-Hz tones over captain's headset. IF -

T34419
EFFECTIVITYAF 121,122,151-199; LH 051-099; AZ ALL; SN ALL; IB ALL; GN ALL;
703 Page 102
34-32-00
AT ALL; MD ALL; VM ALL Sep 25/94Prepare for troubleshooting as described in par. 2. Press each marker beacon indicator light on captain's and first officer's instrument panels. Check that each indicator light comes on when pressed. IF -

Set test generator to provide 400-Hz test signal. Check that blue marker beacon indicator comes on and listen for 400-Hz tone over captain's headset. Set generator to 1300-Hz. Check for amber indicator and 1300-Hz tone. Set generator to 3000 Hz. Check for clear indicator and 3000-Hz tone. IF -

System is operable.

T34425
EFFECTIVITY AF 101-120,123-150; LH 001-050

703 Page 103
Sep 25/94
34-32-00
PROCEDURE 1

EFFECTIVITY ALL

703 Page 104
34-32-00
 Oct 10/73
 MARKER BEACON SYSTEM - ADJUSTMENT/TEST
______________________________________
 1.  General
_______
 A.  Two test procedures are described; the operational test using the self-test facilities of the marker beacon receiver, and the system test is used with an external marker beacon test set.
　
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