User's Manual

Digital UHF Driver/Transmitter Chapter 5, Detailed Alignment Procedures
LX Series, Rev. 1 5-1
Chapter 5:
Detailed Alignment Procedures
5.1: System Preparation
This transmitter was aligned at the
factory and should not require additional
adjustments to achieve normal operation.
This exciter/amplifier of the LX Series
driver/transmitter is of a Modular design
and when a Module fails that module
needs to be changed out with a
replacement module. The replacement
module can then be sent back to Axcera
for repair. Contact Axcera Customer
Service Department at 724-873-8100 or
fax to 724-873-8105, before sending in
any module.
5.1.1: Module Replacement
Module replacement on the LX series
products is a relatively simple process.
All modules plug directly into the
backplane board except for the power
amplifier module, and in higher power
units, the power supply and power
amplifier modules, which plug into a
blind mating connector. To replace a
module, refer to the following
procedure.
Loosen the two grip lock connectors,
located on the front panel, at the top
and bottom of the module,
counterclockwise until the module
releases. The Modulator, IF Processor,
Upconverter and Controller/Power
Supply can then be gently pulled from
the unit. To remove the Driver/Power
Amplifier Module in the exciter/amplifier
chassis assembly, the two cables, Input
and Output, connected to the rear of the
chassis must be removed. These two
cables and also a 6/32” x ½” shipping
screw, located between the two
connectors, must be removed before the
module will slide out. After removal of
the failed module, slide the replacement
module in place and make certain it
connects to the backplane board. If the
replacement module is a driver/PA
Module replace the two cables to the
rear of the exciter/amplifier chassis
assembly. The 6/32” x ½” shipping
screw does not need to be replaced. It
is only used during shipping. If the
replacement module does not slide in
easily, verify it is properly aligned in the
nylon tracks, located on both the top
and bottom of the module.
Note: Each Module has an assigned slot
and will not fit properly or operate in the
incorrect slot. Do not try to place a
Module in the wrong slot as this may
damage the slot or the connectors on
the backplane board. Each module has
the name of the module on the front,
bottom for identification and correct
placement. The Modules are placed in
the unit from left to right; (1) Blank
panel, (2) Blank panel, (3) IF Processor,
(4) LO/Upconverter, (5)
Controller/Power Supply and (6) Driver
Power Amplifier.
5.1.2: Initial Test Set Up
This exciter operates using a single MPEG
input to J12 on the rear of the Exciter
assembly. Check that the RF output at
the coupler is terminated into a dummy
load of at least the rated output of the
transmitter. While performing the
alignment, refer to the Test Data Sheet
for the transmitter and compare the final
readings from the factory with the
readings on each of the modules or tray.
The readings should be very similar. If a
reading is way off, the problem is likely
to be in that module or tray. Switch On
the main AC for the system and the
ON/OFF circuit breaker on the rear of the
amplifier chassis assembly.
5.2: LX Series Exciter Chassis
Assembly
The exciter chassis assembly operates
using a digital IF input from the DM8-R
modulator IF output jack J4 that