User's Manual

2-3
circuits. When used with late model TEN-TEC
transceivers, this jack is not used. When used
with other transceivers, this jack is connected to
the normally open (grounding) contacts of the
relay key out jack of the transceiver.
2.3.6 ALC: This jack provides a negative going
ALC voltage, used primarily with tube type
transmitters/transceivers. See section 1.8 for
detailed information.
2.3.7 ALC CONTROL: This control adjusts
the ALC threshold voltage from approximately -
1 to -15 VDC depending on RF input from the
transceiver.
2.3.8 AC LINE: This cable is connected to
standard 240 VAC. Be sure the line used to
power the TITAN III is capable of supplying 20
amps of current at 240 VAC, and that it is
protected by either fuses or circuit breakers of
20 amps. Wire size of the AC feed line should
be at least 10/2 with ground or larger.
2.3.9 LINE FUSES: Primary line fuses (ABC-
20) are accessible through these panel fuse
holders. Replace with ABC-20 or comparable
fuses only.
2.4 INITIAL TURN-ON: The following
steps should be followed when turning on your
TITAN III.
A. Set multimeter switch to the plate voltage
(Ep) position.
B. Place the power switch to ON. If any of
the following do not occur, press OFF at
once and investigate before proceeding.
1. The power switch light should light.
2. The meter lights should light.
3. The fan motor should start and air
flow should be felt at the exhaust port
on top of the amplifier.
4. The wait LED should light.
5. All meter indications are zero.
6. All other LEDs are not lit.
NOTE: HIGH VOLTAGE IS PRESENT ONLY
IN THE OPERATE MODE. THE OPERATE
MODE IS DISABLED FOR 3 MINUTES
WHILE THE WAIT LED IS LIT.
2.5 TUNE UP PROCEDURE: The
following section describes important points
to observe during tune up. A suggested
procedure for safely tuning up the TITAN
III is included.
2.5.1 CHECKS TO MAKE BEFORE
TUNING UP: Check the load connected to
the amplifier. This can best be done by
leaving the TITAN III in the BYPASS
mode and using only the transceiver output
power. Use a reliable SWR bridge or
wattmeter to determine the SWR of the load
(antenna) connected to the amplifier. If the
reflected power is less than 10% of the
forward power, the VSWR is less than 2:1.
If the reflected power is 4% or less, the
VSWR is 1.5:1 or lower. A VSWR of 2:1 or
less is essential.
2.5.2 IMPORTANT POINTS TO
REMEMBER: The most important
parameters to observe during tune up are the
control grid current and screen grid current.
Excessive grid current even for a relatively
short period of time can and will damage the
tube. If grid currents are not exceeded, the
4CX800A tubes will deliver many years of
trouble free service. In the TITAN III the
control grid is monitored by front panel
LED indicator. When control grid current is
exceeded, the GRID overdrive LED will
light. Reduce the drive immediately and
retune the TITAN III. Screen grid current is
monitored by the multimeter, (when in the Is
position) and by an LED overdrive indicator
continuously. Screen grid current should be
kept to a minimum during tune up and
always in a positive direction. When screen
current is exceeded the SCREEN overdrive
LED will light. Reduce drive immediately
and retune. After tune up, erratic lighting of
either overdrive indicator could indicate
breakdown in the load (antenna
components). Reduce drive and check for
arcing or heating of baluns, coax or other
elements. Brief blinks of the LEDs at initial
power-on or key-down are OK.