(2)  
Verify ATC 1 and 2 circuit breakers on panels P6 and P18 are closed.

(3)  
Select STBY on ATC control module, allow at least 1 minute warming time.

(4)  
After system warmup, set up and operate appropriate ATC system in mode A.

(5)  
Activate ATC system self-test (on transponder or control module). Verify reply/monitor light comes on.

(6)  
On ATC control module position function selector to STBY or OFF as appropriate.

(7)  
Remove electrical power if no longer required (Ref 24-22-0).

3.  System Test - ATC System - Using Collins 476X-3 Test Set
A.  General
(1)  The system test is a complete system checkout of the ATC. The first part of the system test consists of the performance of all tests possible using only the built-in test capability of the equipment installed in the airplane (operational test). The balance of the system test requires the use of an ATC ramp test set.
B.  Equipment and Materials
(1)  
ATC Transponder Ramp Test Set - Collins 476X-3

(2)  
Portable pressure equipment to simulate 0 to 35,000 feet altitude (Ref 34-11-0)

C.  Referenced Procedures
(1)  
34-11-0, Adjustment/Test (Apply Pressure)

(2) 
 34-12-0, Adjustment/Test

(3)  
34-53-0, Adjustment/Test (Operational Test)

5C8
Jun 20/88 34-53-0 Page 501
BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details.

D.  Prepare for Test
(1)  Prior to the use of the ATC transponder ramp test set, Collins 476X-3 in the ATC system test, the following calibration and self-test of the 476X-3 should be performed.
(a)  
Set 476X-3 MODE selector switch to A-B-C, and verify that mode flags indicate A to B to C in sequence.

(b)  
Set MODE selector switch to self-test position and set T/R ATTEN control to 25 dB. Observe that meter indicates to the right of RECHARGE. If meter indicates to the left of RECHARGE, the battery must be recharged before tester is used.

(c)  
To calibrate the R-F OUTPUT, set MODE SELECTOR to SELF-TEST. Position CALIBRATE OUTPUT-BATTERY VOLTAGE switch in calibrate output position, and adjust OUTPUT to obtain a redline indication on meter.

(d)  
To self-test, set MODE SELECTOR switch to SELF-TEST, and set T-R ATTEN control to 25 dB. Observe that IDENT flag appears. 1) Set code selector to 0000 code. Observe that CODE and IDENT flags appear in

steady state. 2) Set code 7777. Observe that CODE and IDENT flags appear in steady state. 3) Set code 7773. Observe that CODE flag blinks; IDENT flag appears in steady
state. 4) Set code 0004. Observe that CODE flag blinks; IDENT flag appears in steady state.
(2)  
Place 476X-3 ramp test set at a distance of between 46 and 50 feet from ATC antenna in a position easily visible from the cockpit, and with an unobstructed radiation path between tester and antennas.

(3)  
Orient tester such that inside of opened cover (antenna element) faces airplane antennas.

(4)  
Position controls on test set as follows:
Function Selector - A-B-C
R/T ATTN dB - 10
Code Switches - Any desired code.

(5)  
Ensure ATC system and altitude source (altimeter or CADC) circuit breakers on panels P6 and P18 are closed.

CAUTION:  IN THE FOLLOWING TEST DO NOT SELECT CODES 3100, 7500, 7600, and 7700. THESE ARE EMERGENCY CODES.
E.  Test ATC System Using Collins 476X-3 Test Set
(1)  
Perform ATC system operational test procedure provided in 34-53-0, ATC System -Adjustment/Test.

(2)  
Position controls on ATC control panel as follows: ALT RPTG - OFF Code Switches - Same as on test set Function Selectors - Activate appropriate ATC system for normal operation in mode A

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34-53-0 Page 502  BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details.  Jun 20/83 

Observe test set, verify code flags appear each time mode A flag appears.
NOTE:  The presence of a strong signal from a nearby ground beacon may override the test signal from the 476X-3 and produce incorrect test results.
(3)  
Change test code selection on both ATC control module and test set to test code compliment. Compliment of test code is 7777 minus test code being used. This checks the full code capability of the transponder under test.

EXAMPLE: If test code being used is 0340, the compliment is:
　
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