Amplifier Research 200T4G18, Operating And Service Manual

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Model 20T4G18
To deactivate Sleep Mode locally:
Press the ON soft key to de-activate Sleep Mode. Amplifier will return to MENU 1. When de-activating the
Sleep Mode the heaters will require approximately a 5 minute heater time delay. Wait the full 5 minutes prior
to selecting OPERATE.
For remote activation of Sleep Mode or to set the Auto Sleep Mode timer remotely see Table 3 in Section 3.8.
Warnings Screens - From MENU 3, S1 (labeled WARNINGS) selects WARNINGS 1 which allows the
operator to enter the maximum forward power. The existing value is between brackets[]; pressing SET puts
arrows >< around the value, indicating that the adjust knob is active. The effect of the warning setpoint is as
follows: if the forward power exceeds the setpoint, the audible alarm will sound (if configured in SETUP 3).
This warning will be repeated every thirty seconds until the over forward power condition is cleared. In
addition, a warning message will appear on line 3 (the status line) of MENU 1. In the event that the alarm is
heard, the operator should go to MENU 1 to determine the cause.
Pressing more brings up WARNINGS 2, which allows the under forward power setpoint to be entered.
Adjusting this to the minimum value causes -OFF- to be selected, disabling this alarm.
In WARNINGS 3, the maximum reverse power level is set. Note that these are warning levels at which the
beep sounds; the actual maximum reverse power level that generates a system fault is set in hardware in the
TWT power supply HPA Logic and Control module (A16485).
MORE brings up WARNINGS 4, which allows input of the maximum cabinet temperature. Entering this
parameter is performed as above.
MORE brings up WARNINGS 5, identical to the previous screen except that it deals with the maximum TWT
collector block temperature. If either parameter exceeds the setpoint, the audible alarm will sound every 30
seconds (if configured), and a warning message will appear on line 3 of MENU 1.
From WARNINGS 5, MORE brings up WARNINGS 6, which permits setting the maximum helix current.
Any helix current above this setpoint will result in an audible alarm (if configured), repeated every 30
seconds; and a warning message is displayed on the status line of MENU 1.
Pressing MORE again returns display to WARNINGS 1. As before, pressing EXIT from any of the warnings
screens returns display to MENU 3.
Info Screen - From MENU 2, S2 (labeled INFO) selects a screen that displays the RF sample port calibration
factors at various frequencies across the band. In addition, this screen displays the model number, serial
number and firmware revision information which may be required by a service representative when providing
technical assistance. The EXIT key returns the display to MENU 2.
Event Screen - From MENU 4, S2 (labeled EVENT) provides a display of events logged by the control
system. These events include AC power-up, heater warm-up, change from standby to operate, faults, and
resets. The events are stored in a first-in-first-out (FIFO) software buffer that has room for 100 events; as new
events are logged, the older ones are discarded.
System Shutdown Screen - In the event of a system shutdown due to a latched fault (i. e., a fault such as body
overcurrent or power low line that requires a reset), the MENU screen is replaced by a screen indicating the
nature of the fault. Softkey S4 (labeled OK) is implemented as a reset key; pressing S4 brings back the
MENU screens. Line 3 of MENU 1, which normally displays the operational state of the TWTA, is used as a
fault display line until the fault is cleared. When the fault clears the system will automatically resume the
standby state and high voltage on will be enabled once again.
14 Rev B
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