______________________________________________HARRIS
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WARNING: Disconnect and lockout AC primary power prior to servicing
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STEP 5: Slowly raise the aural power drive while observing VSWR and FORWARD
POWER. Note, in a multiple PA cabinet system also observe the REJECT POWER(s).
Stop at approximately 50% forward power. Check to be certain the combined output at
each hybrid in a multiple PA system is higher than the reject load for the hybrid. If any
reject load power is higher than the hybrid's output, this suggests a phase error in drive
cabling. Check that drive cable connections are correct and the correct length. Verify the
hard line lengths follow the installation guidelines.
STEP 6: Phase and Gain module alignment: A single cabinet transmitter will not
have any phase and gain units, A two PA system has one phase and gain module, the
procedure is performed only once. In a 3 PA systems, perform this sequence on the lower
level (A / B) phase and gain module, then proceed to the top level ([A+B] / C) module. In 4
PA cabinet systems, begin with the (A / B) and (C / D) phase and gain modules, then
proceed to the top level ([A+B] / [C+D]) module.
STEP 7: Adjust phase and gain module phase control for minimum reject power.
STEP 8: Adjust gain control for minimum reject power.
STEP 9: This completes the phase and gain module alignment in two PA system.
For larger systems, proceed to the next phase and gain module.
STEP 10: Using an external power meter or calorimetric metering to confirm
power output, slowly increase power to 25%.
NOTE:
If external power meter and user display panel readings do not agree, refer to the
power calibration procedures in Section 2.16.
STEP 11: Increase power slowly to 50%. In multiple PA systems, watch the reject
load power while increasing drive, and make slight readjustments to the
phase and gain module controls as above if necessary. Note that the
second half of the green LED on each Aural PA module illuminates, indicating presence of
RF drive.
STEP 12: Compare DC INPUT POWER and 50 volt supply currents to factory test data.
STEP 13: Check all PA modules for output one at a time by squeezing the disable
switch for each module and noting a drop in power output of the cabinet as seen on the PA
cabinet power information screen. Re-enable each module using a transmitter ON
command before proceeding to the next module. Wait 5 or 10 seconds for the re-enabling
of the module to take effect. Each module turn off should cause approximately the same
change in cabinet power output. Remember this requires AGC to be turned off.
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