User Manual

MXi DUAL PALLET OPERATIONS AND MAINTENANCE
PUB06-78 Rev 1 July 17, 2007 06-78-4 MXi Dual Pallet Operations and Maintenance
3 AMPLIFIER INSTALLATION AND STARTUP
The MXi Amplifier was fully tested at LARCAN before it was delivered. Under normal circumstances, the
transmitter can be fully operational with minimal setup when turned ON. However, a good practice is to take the
“start from scratch” approach, which means that you should take precautionary measures before the amplifier is
allowed to run at full rated power. These important steps will avoid any catastrophic failures at start-up. The
procedure described is essentially the same approach taken at the factory with a new and untested transmitter.
This also applies if there is a need to completely replace a major sub-assembly in the transmitter.
3.1 BEFORE APPLYING AC TO THE UNIT
Pay careful attention to items 1 to 3 before applying AC to the amplifier. These are initial steps that must be
observed and followed for proper and safe operation of the amplifier.
1. Termination
• Ensure that the amplifier is properly terminated with a suitable load. This can be into a dummy load or into
the transmitter output system. A 50 Ohm, 100W load with at least –20dB return loss (1.2 VSWR) is
recommended. Preferably, directional couplers with known coupling levels at the frequency of interest
should be connected at the input and output of the band-pass filter. These points are very useful in
determining absolute power levels and losses and for use as an RF sample for monitoring purposes. See
Figure 15 for a typical transmitter test equipment setup.
2. Interlocks
Interlocks must be connected to the amplifier to avoid damage to the equipment and to the output section.
Interlock is provided at the INTERLOCK terminal board located on the rear panel. If this interlock is open, the
B+ to the amplifier will shut down, including the cooling fans. DO NOT replace this interlock with a jumper.
Figure 7 Rear Panel Showing Interlock Terminal Board
3. Power At Minimum
• Initially, the Exciter or Channel Processor’s RF output should be at minimum level. Adjust the OUTPUT
LEVEL control for a minimum output.
3.2 APPLYING AC TO THE UNIT
• Check that the AC voltage available to the amplifier ranges from 90-264VAC. If so, proceed to applying
the power to the AC INPUT of the amplifier
• Once the AC is applied to the unit, the Control Power Supply turns ON and applies +12V to the MXi
Controller.
• Observe that the Power-Up screen is displayed on the LCD, followed by the Main Menu.