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Fig. 4-1 – Appearance of an alarm message
a) The first protection level is the WARNING type. Only a warning message appears on the screen
accompanied by a sound signal, but without any physical reaction from the amplifier – Fig. 4-1. This
occurs when some of the values monitored by the control unit approach too close the threshold of
tripping the respective protection. The transmission is not interrupted, but a message appears – for
example “Drive Power too High”, “Drain Current too High”, or another.
You can continue to transmit in these conditions, but you also have to take some measures, for example, to
reduce a little the drive power from the transceiver, because the respective protection trip will be too close. The
warnings for the first level remain on the screen for at least three seconds so that they can be read through and
they disappear by themselves after the reason has dropped off.
b) The second protection level is the SOFT FAULT type – it trips at crossing the threshold of some
protection, as long as it had not been fatal (then the third level trips – see item (c) below).
At the second level (SOFT FAULT) the amplifier itself does not turn off fully but only returns into Stand-by mode
for four seconds or permanently - depending on whether the “AUTO OPERATE” option had been activated. Return
into Stand-by mode is accompanied with the respective message on the screen, for example “Excessive Reflected
Power”, “Excessive Drain Current”, and others, as well as with a sound signal (unless its volume had not been
decreased to zero – S. 5-4).
Unlike those for a WARNING, the SOFT FAULT messages remain on the screen and persist until the operator
presses any button (including the two unused in the basic screen) - thus it is understood that he has read the
message - or until the AUTO-OPERATE function returns automatically the OPERATE mode if the option is active
– S. 5-4.
SOFT FAULTs presume performing fast and simple correcting actions by the operator, such as, for example,
reducing the drive power, improving of load SWR through retuning of the antenna tuner, selection of another
antenna, another frequency etc.
c) The third and most serious protection level is the HARD FAULT type, which turns off the amplifier
automatically to avoid possible further damages.
At tripping the third level of protection, the amplifier turns off its main power supply automatically, stores all data
about the fault in its nonvolatile memory, the front panel screen blanks and a specific sound signal is emitted
(namely a series of Morse letters F, which continues until the control unit still has residual energy).