Linnenberg WIDOR Owner's Manual page 6

There is no need to operate the mains ON / OFF
switch on the back side since the standby
power consumption is less than 0,5W. As it is
common practice, disconnect WIDOR from the
mains during a thunderstorm or when going on
vacation.
Protection circuits
WIDOR provides comprehensive protection for
both the amplifier and your loudspeakers,
including faults that may occur in your source
components.
If the unit is operated at high playback levels
with insufficient ventilation, the internal
temperature may become too high, triggering
the thermal protection circuitry. In this case the
amplifier will shut down, the front-panel status
LED will blink at a fast rate.
Likewise, if the surveillance circuit detects the
presence of DC at the output terminal, the
amplifier will shut down too. Unallowable DC
voltages can origin from the source component
or the WIDOR amplifier itself. To isolate the
source of the problem, disconnect the audio
input cable from the WIDOR amplifier before
proceeding any further.
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