Pulsar LPA100, System Manual

Page: 35 / 66

Copyright © 2001 Pulsar Technologies, Inc.
Chapter 5. Installation and Initial Adjustment
5
5.1 INITIAL ADJUSTMENT
Following are step-by-step procedures to properly
power up and do initial adjustment on the LPA50
and LPA100. These procedures are only intended
for use with a properly working LPA that still has
its factory settings. Basically only the input power
to the LPA needs to be set, since all the other
adjustments were made before shipment. Refer to
Figures 5-1 for module and test point locations. If
there are any problems with this procedure or if a
new module that did not originally ship in these
chassis is being inserted, then please refer to the
calibration/troubleshooting procedure in section
5.2.
5.1.1 LPA50 Adjustment Procedure
1. Verify proper connections per the connec-
tion diagram, Figure 5-2. Terminate the
output of the LPA50 (coax connector J9),
that would normally connect to the line
tuner, with a 50
Ω
non-inductive resistor
rated at 50W.
2. Turn the INPUT LEVEL potentiometer on
the driving carrier set’s Power Amplifier
module to
minimum (fully counterclock-
wise). This will prevent it from overdriving
the LPA when initially powered up.
3. Turn on all the Power Supply modules one
at a time noting that both the INPUT and
OUTPUT red LEDs come on for each
Power Supply module. If all the power
supplies are not turned on within a few
minutes of one another, the Power
Combiner module(s)’s balance resistors
will heat up which is normal since only part
of the Power Amplifier modules would be
energized causing imbalance in the Power
Combiner module. This heating will
disappear after all Power Supplies are
turned on and all the Power Amplifier
modules are energized.
4. Turn on the driving carrier set.
5. With the carrier’s set transmitter on, on any
one of the four 12.5W Power Amplifiers in
!
CAUTION
BE CAREFUL TO NOT LET THE TEST POINTS
SHORT TOGETHER SINCE THEY ARE PHYSI-
CALLY CLOSE TOGETHER.
Technologies, Inc.
Power Sequence Quick Reference
Power Up Sequence:
Turn all LPA Power Supplies on first before energizing any
driving carrier set.
Power Down Sequence:
Power down the driving carrier set before turning off any
Power Supplies in the LPA.