Off-center tuning may also be used to compensate for line (mains) voltage variations in order to maintain
tube efficiency. In that case, tune to the left when line (mains) voltage is high, or tune to the right if it is
low. However, where there is more than a 10% difference from the nominal line (mains) voltage, the
voltage selector inside the amplifier should be changed (see Section 2.2 Line Voltage Selection).
4.6. The Auto-Protection System
When any abnormal amplifier condition is detected, the risk will be evaluated automatically and either of
two degrees of protection will be applied by the controller.
Degrees of protection:
a) First degree of protection - An illuminated LED warning
These include the yellow LED warnings described in Section 3 POWER ON, CONTROLS AND INDICATORS, i.e.,
"G1" (grid 1), "G2" (grid 2), and "IP" (plate). Operation may be continued but the amplifier is likely to
proceed to the second degree of protection, the trip.
b) Second degree of protection - A trip to the STANDBY mode
The red "F" (fault) LED illuminates and the amplifier automatically goes to the standby mode for several
seconds. Also, the green OPER LED goes off. The amplifier will indicate the reason for the protection trip:
• If one of the yellow (G1, G2, IP) warning LEDs is illuminated along with the red "F" LED, a
current limit has been exceeded and drive power must be reduced or retuning is necessary
(see Section 4.5 Tuning);
• If the last red LED of the reflected-power bar-graph is illuminated together with the red "F"
LED, the reflected-power limit has been exceeded and the drive must be reduced or the
antenna SWR must be improved;
• If all three LEDs of the TRI indicator above the LOAD knob are flashing simultaneously
together with the red "F" LED, the tuning is not adjusted correctly or the antenna impedance
has changed and retuning is required (see Section 4.5 Tuning).
Fault information normally remains on the display for several seconds while the amplifier is in the standby
mode. The auto-operate function will attempt to return the amplifier to the operate mode automatically as
described in Section 4.2 Changing OPERATE and STANDBY Modes. If the protection trips repeatedly, the user
must attend to the cause of the trip, which is typically too much drive or antenna mismatch.
NOTICE
If all LEDs in the bar-graph area are flashing simultaneously, you must immediately
switch off the amplifier to avoid damage.
To Next Page
Loading...
Need help?
General
