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4.5.4 Power Supply Faults
The Power Supply Fault circuit monitors the 28 VDC, ± 12 VDC and 5 VDC power supplies and
produces a fault indication should any voltage level deviate from normal operating parameters.
Each power supply voltage output is monitored and Green Status LEDs are illuminated to
indicate that the power supplies are operating within design parameters. Should any power
supply voltage deviate from the design parameters, the corresponding Green Status LED will
extinguish. The Power Supply Fault Indication LED, located on the front panel of the Power
Supply / Control Module is illuminated RED only when the 28 VDC power supply fails to meet
design tolerances in addition to the extinguishing Green Status Indicator LED. A ± 12 VDC or
5 VDC power supply failure will not illuminate the Power Supply Fault Indication LED, this
indicator is reserved only for the 28 VDC supply.
4.5.5 Mismatch Protection
The CMX25 is designed to operate with a tuned 50 Ohm load and should any mismatching of the
50 Ohm occur, the Reverse Power, also called Reflective Power, will increase producing a high
VSWR. The CMX25 microprocessor monitors the Reverse Power levels by utilizing a Dual
Directional Coupler and begins to turn down the gain of the preamplifier when the Reflected
Power exceeds 25%. The Reverse Power is also displayed on the LCD Display for operator
monitoring for any mismatched load.
4.5.6 Modular Faults Indications
The CMX25 is a microprocessor controlled wide band power amplifier which the
microprocessor is designed to control and monitor critical components within it's circuitry. If the
microprocessor detects any abnormality, the microprocessor generates and stores up to 13
diagnostic fault codes which are scrolled on the LCD Display as a trouble shooting aide for the
operator. The CMX25 also has a RED Status Fault Indicator LED which illuminates when any
fault condition occurs.
4.5.7 Short Circuit Protection
The CMX25 utilizes three different power supply voltages, + 28 VDC, ± 12 VDC and the
+ 5 VDC, each of the power supplies are designed with a short circuit and overload protection
device.
