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Alpha 9500 Linear Amplifier User Manual
RF Concepts, LLC
Diagnosing Faults
Product Release 1
DOCNUMBER 9500
Document Issue 1.1
Page 8–8
February 2010
88
8
occludes the opto-interrupter. This position is registered as a 0 (zero) for
the load capacitor, and represents the minimum attainable capacitance for
that capacitor. Maximum capacitance is attained when the stepper motor
controlling the load capacitor has taken 100 steps. The stepper motor
controller counts how many steps it takes, adding when the capacitance
increases and subtracting when the capacitor decreases. The count
(between 0 and 100) is the load capacitor position. When the master
controller (MC) sends a command indicating that a new load capacitor
position is desired, the stepper motor controller knows in which direction
and for how many steps to turn the capacitor.
the load capacitor, and represents the minimum attainable capacitance for
that capacitor. Maximum capacitance is attained when the stepper motor
controlling the load capacitor has taken 100 steps. The stepper motor
controller counts how many steps it takes, adding when the capacitance
increases and subtracting when the capacitor decreases. The count
(between 0 and 100) is the load capacitor position. When the master
controller (MC) sends a command indicating that a new load capacitor
position is desired, the stepper motor controller knows in which direction
and for how many steps to turn the capacitor.
Resolution
1. Unplug the amplifier, wait 30 seconds, and plug it back ON to the
ON2 or ON/AMP setting.
2. Even if the last fault is still fault 10, attempt to turn the load capacitor
from the buttons on the front panel or from the AR9500 PC
application. If the capacitor responds, the fault may have cleared.
application. If the capacitor responds, the fault may have cleared.
3. If the fault persists, contact RF Concepts technical support. If
possible, send them the contents of the fault log. To display the fault
log, from the AR9500 PC application, open the Fault window and
select Tools > Get fault log.
log, from the AR9500 PC application, open the Fault window and
select Tools > Get fault log.
Fault code 11
Description
Over-temperature.
Explanation
The amplifier has a built-in temperature sensor to ensure that the tube
does not overheat. The sensor is located on the cathode board, in the tube
deck compartment. Air from the blower motor impinges on this board and
then flows up through the tube anode fins. Normally the temperature it
reports is at approximately this air temperature. Since the air has already
been drawn over other parts of the amplifier, it is some 10–20C warmer
than ambient air. The trip value is currently set to 50C.
does not overheat. The sensor is located on the cathode board, in the tube
deck compartment. Air from the blower motor impinges on this board and
then flows up through the tube anode fins. Normally the temperature it
reports is at approximately this air temperature. Since the air has already
been drawn over other parts of the amplifier, it is some 10–20C warmer
than ambient air. The trip value is currently set to 50C.
The amplifier goes to ON AMP, but in bypass mode and with the tube
biased off. This should reduce plate dissipation to a minimum and, if the
air system is working correctly, the temperature should start to fall. When
it reaches a safe value, the amplifier can be put in service again, as
indicated by fault code 13 (clear temperature).
biased off. This should reduce plate dissipation to a minimum and, if the
air system is working correctly, the temperature should start to fall. When
it reaches a safe value, the amplifier can be put in service again, as
indicated by fault code 13 (clear temperature).
Resolution
1. Ensure that there is air exiting the amplifier from the hexagonal
pattern of holes near the rear left. If not, this is likely the cause.
2. If there is no air leaving the amplifier when it is in the ON AMP
position, assuming that all other front panel displays appear normal,
ensure that there is nothing obstructing the air flow at the inlet (on the
right rear of the amplifier) or at the exit.
ensure that there is nothing obstructing the air flow at the inlet (on the
right rear of the amplifier) or at the exit.