Tube Red Fault - VTL S-400 II series Owner's Manual

Green TUBE indicators, unit in operate mode
Check the output tube LED indicator on the amplifier deck to locate the tube that has the non-critical fault and
follow the procedure described in Chapter 4 to replace that output tube.

TUBE red Fault

Where an output tube draws excessive current and cannot be controlled by the autobias system the amplifier
needs to be shut down and the faulty tube indicated on the front panel.
The flashing red TUBE indicator indicates that one of the output tubes has a critical fault that requires that the
amplifier be immediately shut down to prevent damage to the amplifier circuits. In this condition the amplifier is
in the standby mode with the LED indicators showing what to do to re-start the amplifier.
The tube number is displayed on the front panel display, and the top deck LED next to the indicated tube is
blinking quickly to show the exact location of the tube. The steady blinking on the failed tube will continue to
blink while the amplifier is in the standby condition, and all the other LEDs are off.
Check the output tube LED indicator on the amplifier deck to locate the tube that has the critical fault. Follow
the procedure described in Chapter 4 to replace the output tube, and then clear the red TUBE fault light by
performing the following procedure, informing the amplifier that the faulty tube has been replaced:-
Reset Red Tube Fault
S-400 Amplifier Owner's Manual 41
VTL