Harris Platinum Series, Technical Manual

Page: 32 / 158

CAUTION
INIT PHASE MUST BE PROPERLY SET TO MINIMIZE REJECT
POWER UPON RETURN FROM A POWER FAILURE.
2. Alternately adjust A and B gain pots for minimum reject
power.
3. Set phase to RUN position and /- phase control
for minimum reject power.
4. This completes the phase and gain module alignment in
20 kW and 30 kW systems. For larger systems, proceed
to the next phase and gain module.
h. Using an external power meter to confirm power output,
slowly increase visual power to 50%.
If external power meter and user display panel readings do
not agree, refer to the power calibration procedures in Sec-
tion V.
i. Increase power slowly to 100%. In 20 kW and higher
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 visual PA module illumi-
nates, indicating presence of RF drive. In some cases where
transmitter power is significantly less than 30 kW, the PA
modules used in the drive stage may illuminate only half
of the green LED even though full RF drive is applied.
j. Compare DC INPUT POWER and 50 volt supply currents
to factory test data.
k. LOWER power to 66%. Switch AGC off and RAISE
power back up to 100%.
l. Check all 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 visual (or aural)
information screen. Re-enable each module using a trans-
mitter ON command before proceeding to the next.
m. Switch AGC back ON when done and RAISE power to
100%.
n. Compare AGC reading on the display and voltages at the
test points on front of the module to the factory test data.
o. Refer to AGC adjustments in Section V if needed.
p. Refer to exciter manual for adjustment of the following:
Depth of modulation
Differential gain
Incidental phase (ICPM)
Differential phase
Amplitude response and group delay compensation (Ex-
citer Group Delay Compensator and Notch Diplexer
Equalizer adjustments)
Power limit
Frequency
2.13.2
Aural
a. Slowly apply aural exciter drive while watching VSWR
and FORWARD power. If a notch diplexer or hybrid output
combiner is used, check its reject load power as well. Stop
at about 50% and use external power metering to confirm
power.
b. In higher power systems, if one or more phase and gain
modules are used in the aural paths, adjust them as in the
visual procedure above.
c. While watching reject load power(s) if applicable, slowly
RAISE power to 100%. If the system has aural phase and
gain module(s), recheck their adjustments.
d. Check the user display panel readings against the external
meter. Refer to power calibration in Section V if needed.
e. Check each aural PA module for output using the same
procedure as outlined for visual PAs (steps 2.12.1.k-m).
f. Apply either mono audio (and SCA, if used), or a compos-
ite MTS signal, to the appropriate exciter input(s). Refer-
ring to exciter manual, adjust the input level(s).
2-10 888-2365-001 Rev. C: 8-24-2000
WARNING: Disconnect primary power prior to servicing.