AR 10045879, Operating And Service Manual

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Rev A 7
2. OPERATING INSTRUCTIONS
2.1 GENERAL
Operation of the Model 250U1000 broadband amplifier is quite simple. The amplifier’s input signal, whether
swept or fixed in frequency, is fed into the jack marked RF INPUT, and the amplifier’s output signal is taken
from the jack labeled RF OUTPUT . The unit is turned on by activating the front panel POWER switch. In
the event of a major malfunction, protection is provided by a circuit breaker located on the unit’s rear panel.
CAUTION:
The Model 250U1000 Amplifier
will provide 100% of rated power
without foldback into a mismatched load. The amplifier will operate
without damage or oscillation with any magnitude and phase of
source and load impedance.
However, placing the amplifier in the
operate mode without a load connected to the output connector is not
recommended. It has also been designed to withstand, without damage,
RF input power levels up to twenty (20) times its rated input of 1mW.
However, signal levels higher than 20mW or transients with high peak
voltages can damage the amplifier. Also, accidental connection of the
Model 250U1000’s output to its input (either through direct connection or
parasitic feedback paths) will cause oscillations that may permanently
damage the unit’s input transistors.
The 250U1000 RF power transistors are protected from over temperature by sensing the chassis temperature
near the RF output transistors. In the event of a cooling fan failure or an airflow blockage, the DC voltage will
be removed from the RF stages, when the chassis temperature reaches approximately 70°C.
Normal operation can be resumed after the chassis temperature drops below 70° C.
2.2 AMPLIFIER FRONT AND REAR PANELS
Figure 2-1 shows the front panel of the Model 250U1000 Broadband Microwave Amplifier. Figure 2-2
shows the rear panel of the Model 250U1000 Broadband Microwave Amplifier.
Figure 2-1. Model 250U1000 Front Panel