Comtech EF Data HPCST-5000 - Manual (Page 127)

High-Power TWTA Satellite Terminals TWT Amplifiers
Rev. 1 4–9
4.1.4.2 Power-On Sequence
The pin numbers referenced in this section apply to connector J1, the interface
connector.
1. Connect Pin a to ground. This applies prime power to the TWT power supply.
Wait until the heater time delay cycle is complete (Pin G goes low).
2. Connect Pin F to ground. This turns High Voltage ON. The High Voltage ON
status line (Pin K) goes low.
3. Turn on the test RF signal source. Slowly increase the drive power to the
amplifier. Monitor the RF output power though the amplifier’s built-in power
sampler, or though an external coupler.
C AU TIO N
Driving the TWT by more than 2 dB beyond the input power
required to reach the saturation point may cause permanent TWT
damage.
4.1.5 Shut Down
There are three shut down modes:
1. High Voltage OFF, heater at full power.
If the amplifier is to be deactivated for a short time (a few minutes to an hour),
turn High Voltage OFF by disconnecting Pin F from Pin W.
2. High Voltage OFF, heater in standby mode.
If the amplifier is to be shut down for a few hours and quick power-up is
required, disconnect Pin F from Pin W and connect Pin J to Pin W. This places
the amplifier is heater standby mode.
3. Amplifier OFF.
If the amplifier is to be shut down for an extended period, disconnect Pin a from
Pin W. This completely deactivates the TWT and allows the TWT heater to cool.
Note: These actions are performed by the optional TWT controllers.