After the internal temperature of the amplifier goes back to the acceptable range (below 50 degrees C) the Heat LED
turns off automatically, and the front panel displays the standby mode indication, a steady
----, indicating that the unit
can be re-powered.
POWER faults
There are three different power faults: External Power supply faults (AC power), internal power supply
faults not requiring service and internal power supply faults requiring service.
The amplifier automatically shuts down when it detects that either the AC voltage is higher or lower than the
acceptable range or there is an internal power supply fault in the amplifier.
AC fault:
In the case of over or under AC voltage the Power LED blinks and the front panel display shows the
amplifier’s blinking AC voltage setting. This automatically resets when the AC voltage returns to the correct
range, regardless of whether power to the amplifier is lost or not, as the AC voltage sensing re-activates whenever
AC power is applied to the amplifier.
When the amplifier’s AC fault condition is removed, the front panel POWER light turns off and the display
indicates a steady ----, indicating that the amplifier can be re-powered.
If the amplifier was on and shuts down, the steady red power light to indicate what happened. If amp was in
standby mode, it will return to standby mode, when the AC supply returns to normal.
AC Power supply fault shutdown, unit in standby mode
In the case of an internal power supply problem, there are two different conditions displayed:-
1. Over-current fault: An over-current fault indicates a temporary condition for which the amplifier has
to be shut down to protect itself. In this condition the front panel red POWER light is on steady and
the display indicates a steady ----, indicating that the amplifier can be immediately re-powered. If AC
power is lost before re-power the red POWER light will turn off when power is re-applied.
S-400 Amplifier Owner’s Manual
VTL
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