User's Manual

3300-Watt VHF Low Band Transmitter Chapter 2, System Description,
Maintenance & Remote Control Connections
335B, Rev. 0 2-4
2.2 Control and Status of Transmitter
Control and status information for the
transmitter is provided by the meter and
LED indicators on the front panel of the
VHF exciter. The switches and LED
indicators are part of the (A17)
transmitter control board that is mounted
so that the switches and LEDs are
operated or viewed from the front panel
of the VHF exciter.
Switch S1 is an Operate/Standby switch
that controls the output of the
transmitter by providing the Enables
that, when the transmitter is in Operate,
are needed to turn on the switching
power supplies in the three VHF amplifier
trays. When the transmitter is in
Operate, the green LED DS2, located on
the front panel of the VHF exciter. When
it is in Standby, the amber LED DS1 is
on. If the transmitter does not switch to
Operate when S1 is switched to Operate,
check that a dummy jumper plug is
connected to (A12-J9 at pins 21 and 22)
on the remote interface panel. It must
be present for the transmitter to operate.
If the interlock is present, the green LED
DS5, mounted on the transmitter control
board, will be lit.
NOTE: If the remote interface panel is
not present in your transmitter the
dummy jumper plug must be present on
J11, with a jumper between pins 23 and
24, located on the back of the VHF
exciter tray. The jumper provides the
interlock needed for the transmitter to
operate. If the interlock is present, the
green LED DS5, mounted on the
transmitter control board, will be lit.
Switch S2 is an Automatic/Manual switch
that controls the operation of the
transmitter by the presence of the video
input signal. When the switch is in
Automatic, the green LED DS3 is lit and,
if the video input signal to the
transmitter is lost, the transmitter will
automatically switch to Standby. When
the video input signal returns, the
transmitter will automatically switch back
to Operate. In Manual, the amber LED
DS4 is lit and the operation of the
transmitter is controlled by the front
panel switches. During normal operation
of the transmitter, switch S2 should be in
the Auto position. The front panel of the
VHF exciter also has LEDs that indicate a
Video Fault (red LED DS9) and VSWR
Cutback (amber LED DS7).