Specifications

Selector switches are changed. The Antenna VSWR Null
switches are active and can be used to null the front panel meter
position if required.
Q.5.2.2 TUNE And LOAD Multimeters
The LOAD Multimeter is turned off.
If the Tune Meter Select switch is in the Normal position, the
TUNE Multimeter is also turned off. If the Tune Meter Select
switch is in the Multimeter position, the TUNE Multimeter is
turned on and can measure up to 12 meter sample inputs.
Q.5.2.3 Fault Status
The TUNE and LOAD Servo Fault inputs are not active and the
indicators on the front panel are extinguished.
The Frequency Synthesizer, Bandswitch Drivers, and Frequency
Control Fault indicators should be illuminated GREEN. If any
of these faults occur, the front panel indicator will turn RED, the
TUNE and LOAD Multimeters will be turned on, and an RF
MUTE will be applied to the transmitter.
Q.5.3
Frequency Change Mode
In this mode the transmitter is turned OFF and all frequency
adjustments are activated.
Q.5.3.1 Frequency Control
The frequency entered into the Frequency Select switches will
be latched into the Synthesizer when another mode is selected.
It cannot be changed unless the frequency change mode is
entered again.
The TUNE and LOAD Servo Raise/Lower controls are active.
Each Servo Raise/Lower control switch will be adjusted using
the appropriate Multimeter to a Servo Reference Voltage listed
on the Transmitter Band Chart for the selected frequency.
The Antenna VSWR Null switches can be preset to values from
the Transmitter Band Chart.
Q.5.3.2 TUNE And LOAD Multimeters
Both Multimeters will be turned on, and the Servo Reference
Voltages will be displayed. Each Multimeter is used along with
the Servo Raise/Lower controls to preset the appropriate Servo
Reference Voltage listed on the Transmitter Band Chart for the
selected frequency.
The TUNE Multimeter may be used as a Multimeter for checking
meter sample inputs if desired.
Q.5.3.3 Fault Status
All Fault inputs are active, and each front panel indicator should
be illuminated GREEN. If a fault occurs, the front panel indicator
will turn RED and an RF MUTE will be applied to the transmit-
ter.
Q.5.4
STATUS PAL
The purpose of STATUS PAL U3 is to display the mode of
operation and depending upon that mode, control the multimeter
functions and provide fault status indications.
Refer to Figure Q-1, STATUS PAL, for the following discussion.
Q.5.4.1 Mode Indicator Inverters
When the one of the mode inputs to the PAL is logic high, an
inverter connected to an output pin of the PAL will be a logic low
and illuminate the corresponding LED. Note that all indicators
are YELLOW with the exception of the GREEN Normal Opera-
tion Mode LED.
Q.5.4.2 Tune Meter Select Switch
When the Tune Meter Select toggle switch S2 is in the Normal
position, a logic high is supplied to U3-11. This input is con-
nected to the MTR Norm output at U3-17, which causes the Tune
Multimeter to monitor tune servoparameters depending upon the
mode of operation. When S2 is in the M/M position, the logic
low input/output signal causes the Tune Multimeter to switch to
the Multimeter function, regardless of the mode selected.
Figure Q-1. Status PAL
Q-2 888-2339-002
WARNING: Disconnect primary power prior to servicing.