User's Manual

MXi AMPLIFIER CHASSIS
push air from the front panel through the heatsink and through the perforations in the rear panel. This assembly is
located underneath the MXi Controller board.
Figure 17 MXi Fan Array
A thermal switch is mounted on the heatsink where the operating temperature is sensed. If this temperature
increases beyond the trip point of the thermal switch, which is about 60°C, its contact opens and breaks the
interlocking circuit of the MXi amplifier. The interlock circuit ultimately controls the power supply to the power
amplifier and therefore shuts down and remains OFF until the heatsink cools down to about 50°C.
Figure 18 MXi Heatsink Assembly
A directional coupler is also mounted on the heatsink and provides forward and reflected RF signals to the
controller. These RF samples are detected and processed on the MXi amplifier controller to provide DC outputs
corresponding to these signals. They are then used for AGC, VSWR supervision and also for providing digital
metering available on the front panel LCD touchpad.
TSM21Q-365 Rev 0 July 17, 2009 MXi Dual Pallet Amplifier Chassis 25