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Matsushita Avionics Systems Corporation
COMPONENT MAINTENANCE MANUAL
PART NUMBER RD-AA5002 SERIES
23-32-47
(5) RF Stop Test
This test is possible only when your VMU tester software is
MH2HD256005C or MH2HD256005D. With the tester software MH2HD256005A
or MH2HD256005B, you cannot change the channel frequency to "000" to
stop the RF carrier.
(a) Use the same test connections as for the RF4 level test.
(b) Push the F1 key. You will see the message "CHANNEL NUMBER TO
CHANGE FREQUENCY ?".
(c) Type 01 (for channel 01), then push the Enter key. You will see
the message "DESIRED FREQUENCY IN MHz (LESS .25)?".
(d) Type 000, then push the Enter key. You will see that the
frequency for CHANNEL 01 is changed to 000.
(e) Do steps (b) thru (d) for channels 02 thru 12.
(f) Make sure on the spectrum analyzer that the 12 RF carriers are
off.
(g) For each channel, the result is satisfactory if its RF output
level is decreased to:
50 dBmV or less.
(h) Record the channel number if the result is unsatisfactory.
Page 136
Feb 20/2002
Matsushita Avionics Systems Corporation
COMPONENT MAINTENANCE MANUAL
PART NUMBER RD-AA5002 SERIES
23-32-47
G. End of Functional Testing
(1) If all results are satisfactory, go to step (3). If one or more
results are unsatisfactory, go to step (2).
(2) Results Unsatisfactory
(a) Push the F2 key (NORM) and then the Enter key. The channel
frequencies will be put back to the normal set of VHF carrier
frequencies.
(b) Go to "6. Fault Isolation" if the problem is related to the RF
levels and you think you can correct the problem through
adjustments. For the other problems, go to step (c).
(c) Push the F9 key (NEW) and then the Enter key. The program's
first screen (Figure 103B) will come back.
(d) Set the tester's POWER switch to OFF, then go to "6. Fault
Isolation".
(3) Results Satisfactory
(a) If you recorded the channel frequencies at the start of testing,
use the F1 key as in the RF stop test and put the recorded
channel frequencies back to the UUT.
If the normal set of VHF carrier frequencies were set on the UUT
or if the channel frequencies that were set on the UUT are
unknown, push the F2 key (NORM) and then the Enter key.
NOTE: If the channel frequencies that were set on the UUT are
unknown, we recommend to attach a tag to the UUT to show
that the channel frequencies are changed to the factory
setting values (normal set of VHF carrier frequencies).
(b) If there is no other UUT for testing, push the F10 key (QUIT)
and then the Esc key to stop the program.
If you do testing of a different UUT, push the F9 key (NEW) and
then the Enter key. The program's first screen (Figure 103B)
will come back.
(c) Set the tester's POWER switch to OFF. You can put the UUT back
to service.
Page 137
Feb 20/2002
Matsushita Avionics Systems Corporation
COMPONENT MAINTENANCE MANUAL
PART NUMBER RD-AA5002 SERIES
23-32-47
6. Fault Isolation
A. Preparations for Fault Isolation
(1) Disassembly Necessary for Fault Isolation
(a) If the problem is related to the RF levels (too high or too low)
and if you think you can correct the problem through
adjustments, go to step (b). For all other problems, go to step
(c).
(b) Disassembly for Adjustments
1 Keep the tester's POWER switch ON.
2 Remove the top cover assembly [1-10].
(c) Disassembly for Fault Isolation
1 Set the tester's POWER switch to OFF.
2 Remove the top cover assembly [1-10] and bottom cover [1-35].
(2) General Sequence of Fault Isolation, Repair and Functional Testing
Functional testing of the UUT must be completed with all results
satisfactory. Figure 103F shows the general sequence of fault
isolation, repair and functional testing.
You usually do a single test after the repair to make sure if the
problem is corrected. If the problem is corrected, you must
complete the functional testing again to make sure that the UUT is
serviceable.
Page 138
Feb 20/2002
Matsushita Avionics Systems Corporation
COMPONENT MAINTENANCE MANUAL
PART NUMBER RD-AA5002 SERIES
23-32-47
START OF
FAULT ISOLATION
FAULT ISOLATION
REPAIR
SINGLE TEST TO FIND IF
PROBLEM IS CORRECTED
PROBLEM
CORRECTED?
NO
ALL TESTS OF
FUNCTIONAL TESTING
RESULTS OK?
UUT SERVICEABLE
YES
YES
NO
GENERAL SEQUENCE OF FAULT ISOLATION, REPAIR AND FUNCTIONAL TESTING
Figure 103F
Page 138.01
Feb 20/2002
Matsushita Avionics Systems Corporation
中国航空网 www.aero.cn
航空翻译 www.aviation.cn
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COMPONENT MAINTENANCE MANUAL Video Modulator Unit (VMU)(37)
