K73477
505  DME System Binary Coded Data 
Oct 20/84  Figure 3  34-55-02 
Page 11 
BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details. 

DME SYSTEM - TROUBLE SHOOTING
EFFECTIVITY

AP N458AC GJ B2509 and B2510 WA ALL EXCEPT N4502W thru N4530W, N4569N, N4571M, N235WA
1.  General
A.  The tree-type format makes use of the self-test features of the interrogator unit and gives a quick procedure for isolating faults without the use of additional test equipment.
B.  The procedure is written for one DME system. When two systems are installed, trouble shooting may be accomplished by interchanging components.
C.  If the procedures do not rectify the malfunction, airplane wiring should be suspected and checked by reference to the wiring diagram.
D.  Apply primary power to airplane and close DME system and associated flight instrument circuit breakers on panels P6 and P18.
Oct 20/84 34-55-02 Page 101
BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details.

5C8 
34-55-02 Page 102  BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details.  Feb 20/86 

DME SYSTEM - ADJUSTMENT/TEST
EFFECTIVITY
GJ B2509 and B2510

1.  General
A.  This section contains an operational test and two system tests of the DME system. The operational test is intended to be used without tools or test equipment for a relatively quick check of the operational status of the system. Special tools and equipment are required for the system tests.
2.  Operational Test - DME System
A.  Prepare for Test
(1)  
Provide electrical power.

(2)  
Ensure following circuit breakers on P6 and P18 panel are closed:

DME-1 AC
DME-2 AC

B.  Test DME System Operation (No. 1 or No. 2 system)
(1)  On appropriate VHF/NAV control panel, perform the following:
(a)  
Adjust frequency tuning controls for 108.00 MHz.

(b)  
Activate DME TEST. Verify that within a few seconds the appropriate RDDMI indicators display 000.0 miles.

3.  System Test - Using Collins 475D-1
A.  Equipment and Materials
(1) DME Ramp Test Set - Collins 475D-1 (modified for AUTO 5-180/270 feature).
B.  Prepare for Test
(1)  
Provide electrical power.

(2)  
Ensure following circuit breakers on panel P6 and P18 are closed:

DME-1 AC and DC
DME-2 AC and DC
INTERPHONE

(3)  
Place DME test set approximately 40 feet from DME antenna. Ensure there are no obstructions between test set and DME antennas. (Run test on line-of-sight basis).

(4)  
Calibrate ramp test set as indicated in test set instructions book.

5C8
Feb 20/86 34-55-02 Page 501
BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details.

C.  Test DME System
NOTE:  Prior to beginning test, ensure the other DME system VHF NAV control panel is tuned to a frequency other than test frequency.
(1)   
On test set, position controls as follows:

TR ATTEN DB – 15
Function Selector - AUTO 5-180/270
RANGE 180/270 – 270

(2)  
Position switches on VHF NAV control panel as follows:

(a)  
Function Selector - ORIDE

(b)  
Frequency display -108.00 MHz. Verify appropriate RDDMI indicators display 5 +0.1 miles; after approximately 18 seconds, display 270 +5 miles and track inbound to 263 +5 miles, then track outbound to 277 +5 miles; and after approximately 18 seconds, display 5 +0.1 miles.

NOTE:  The above test cycle will repeat as long as function selector switch is in ORIDE position.
(3)  
When DME is locked on, verify DME audio output is available at audio selector panel.

(4)  
On test set position RANGE switch to 180 and function selector to 180/270. Verify appropriate RDDMI indicators display 180+9 miles, track inbound to 173+2 miles and outbound to 187+2 miles.

(5)  
Restore airplane and test set to original configuration and remove electrical power if no longer required.

4.  System Test - Using Instrument Flight Research ATC-600A
A.  Equipment and Materials
(1)  Transponder/DME Test Set - IFR Model ATC-600A
B.  Prepare for Test
(1)  
Position remote test set antenna approximately 21 inches from DME antenna for system under test. Test set antenna should be approximately same height as the airplane antenna.
　
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