Specifications

MXI1002 OPERATIONS AND MAINTENANCE
4
4.1
AMPLIFIER INSTALLATION AND STARTUP
The MXi1002U 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 one 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.
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, 1kW 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 also for use as an RF sample for monitoring purposes.
See Figure 9 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. An
Interlock is provided at the EXT 1 INT’K connector located on the rear panel of the power supply chassis. If
this interlock is open, the +50V to the amplifiers will shut down, including the cooling fans.
Figure 3 Rear Panel Showing Interlock Connector
3. Power At Minimum
• Initially, the modulator output should be at minimum level.
4.2 APPLYING AC TO THE UNIT
• Check that the AC MAINS going into TB1 and TB2 (across L1 and L2/N) ranges from 190-264VAC. If this
is so, proceed to applying power, otherwise, investigate the source of the problem.
• Usually, once the AC is applied to TB1 and TB2, the Control Power Supply turns ON and applies +12V to
the MXi Main controller in the power supply chassis, as well to the controller in each amplifier.
• The Power-Up screen will be displayed on the LCD, followed immediately by the MXi Main Menu.
PUB11-018 Rev 0 July 8, 2011 11-018-5 MXi1002U Operations and Maintenance