User's Manual

351804-1 Rev. 100

COM5000-8 TECHNICAL MANUAL

5.4.1 PA Module Maintenance

For 1.25kW PA Module maintenance refer to the PA Module Interconnect wiring diagram shown in

figure 5.4.1.

The 1.25kW PA Module comprises the following assemblies:

1 ea. PA/Driver/Splitter (heatsink) 351275-1

2 ea. PA (heatsink) 351280-1

1 ea. PA/Combiner (heatsink) 351285-1

1 ea. Harmonic Filter L163184

1 ea. PA Controller PCB L163209-1

1 ea. Fan Interface plate assembly 351289-1

2 ea. 1.25kW PA Module Fans 351293-1

Location of these assemblies is shown in figure 5.4.1A, 5.4.1B and 5.4.1C. The Fans are located on the rear

panel of the 1.25kW PA Module.

Disassembly to gain access to the 1.25kW PA Module assemblies is described in this section. Unless

otherwise noted, reassembling is done in the opposite order of disassembly.

To perform alignment of the 1.25kW PA Module it is necessary to operate the module as a “stand-alone”

Amplifier – while still part of the Transmitter - as follows:

 The 1.25kW PA Module is pulled out of the Transmitter rack cabinet to gain access to

subassemblies.

 The 50V Power Supply is still connected to the PA Module.

 Control connections from the T-4180 are still connected to the System Controller module in order to

provide control (keying, filter selection etc.)

 The T-4180 RF Output connector is terminated into a 50 Ohm Load.

 An RF Signal Generator is used to provide the required drive signal to the PA Module.

 The PA Module is terminated in a 50 Ohm Load/Attenuator with a wattmeter inserted between the

PA Module and the load.