VTL S-400 II series Owner's Manual page 30

applied and tube LEDs are on steady.
Amplifier is in idle mode and tube LEDs are
flickering on and off intermittently.
Music signal is applied and tube LEDs are all
off.
One tube LED is blinking steadily and the
green front panel TUBE light is on. (The
Display Window shows the tube number.)
One tube LED is blinking rapidly and the red
front panel TUBE light is flashing. (Display
Window shows tube number.)
The amplifier is in idle mode and tube LEDs
are all off.
The following diagram shows the layout of the tubes on the top deck and the tube numbering system, which
corresponds to the tube numbers displayed on the front panel in the case of tube fault, or diagnostic
identification:
S-400 Amplifier Owner's Manual
VTL
and the autobias is holding the bias settings steady.
The autobias is changing the tube bias settings to
the optimum setting.
The autobias is out of circuit to allow the output
tubes to properly amplify the audio signal.
The autobias system has detected that this tube is
too low and cannot be biased. User should replace
the tube as soon as possible at the end of the
listening session.
The Auto-bias has detected that this tube has a
critical fault and the amplifier has been shut down.
Replace faulty tube and reset the Tube fault. (See
Chapter 4)
Normal output tube LED display activity is
suppressed. See Basic Programming Functions in this
chapter.
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