User's Manual

2650 Watt VHF High Band Transmitter Chapter 2, System Description,
Maintenance and Remote Interface Connections
435B, Rev. 0 2-6
Table 2-7. VHF High Band Amplifier Tray Fault Indicators
INDICATOR DESCRIPTION
Overdrive (DS1)
Indicates that the level of drive is too high.
The protection circuit will limit the drive
level to the set threshold. The fault is
generated on the overdrive protection
board.
Enable (DS2)
Indicates that the Enable supplied by the
exciter tray is present
Module Status (DS3)
Indicates that the forward power sample
level is lower than the set reference level
VSWR Cutback (DS4)
Indicates that the reflected level of the tray
has increased above 20%; this will
automatically cut back the output power of
the tray. The fault is generated on the AGC
control board.
Overtemp (DS5)
Indicates that the temperature of the
(A4-A5, A4-A6 or A5-A2) thermal switch is
above 175° F. When this fault occurs, the
Enable to the switching power supply is
immediately removed.
Table 2-8. VHF High Band Amplifier Tray Control Adjustments
ADJUSTMENT DESCRIPTION
Phase (A7-R2)
Adjusts the phase of the RF output by
approximately 70°
Gain (A6-R3)
Adjusts the gain of the RF output when the
amplifier control board is in the AGC mode
Table 2-9. VHF High Band Amplifier Tray Sample
SAMPLE DESCRIPTION
RF Front Panel Sample
Forward power sample of the tray from the
AGC control board
2.3 Input Connections
The baseband video and audio inputs
alone or, if the (optional) 4.5-MHz
composite input kit is purchased, the 4.5-
MHz composite input or the baseband
video input and audio input to the
transmitter, connect to the A/V Input &
Remote Interface Assembly, mounted
facing the rear, at the top of the cabinet.
The baseband video input or the 4.5-MHz
composite input connects to jack J2. The
baseband balanced audio input connects
to TB1 or the composite, stereo, audio to
jack J3. To use the 4.5-MHz composite
input kit, the baseband audio can remain
connected even if the 4.5-MHz composite
input kit is used, but the baseband video
must be disconnected from J2 and the
4.5-MHz composite input must be
connected to J2. The baseband select
command must be removed from J7-6
and J7-7.
2.4 AC Input to the Transmitter
The transmitter needs an AC input of 220
VAC at 40 amps connected to it in order
to operate. The 220 VAC input connects
to (A2) the AC distribution panel in the