Heat Fault - VTL S-400 II series Owner's Manual

Remove the front panel Diagnostic cover and locate the buttons labeled TUBE LIFE and TEMP/RESET by
looking at the flashing LEDs that show the buttons to be pressed to clear the fault. Hold down both buttons at
the same time for 15 seconds until the front panel fault indicators turn off.
Located on the top rear panel of the amplifier are two rail fuses that act as a failsafe and will open if for some reason the
fault sensing system does not catch the faulty tube before it draws excessive current. Before powering on the amplifier
again check the Plate and Screen fuses to ensure that they are both good. See the Fuse test section in this chapter for a
description of how to use the internal fuse tester to test the fuses.
Once the fault indicators have been cleared from the front panel the amplifier can be re-powered again using the
POWER button on the front panel.
WARNING: Do not attempt to clear the fault and re-power without first replacing the faulty
output tube, as doing so could potentially damage the circuitry.
If power to the amplifier is lost after a red tube fault shutdown and before the fault is cleared the fault is retained
in memory until the next power up, where the fault will have to be cleared before power up is allowed.

HEAT Fault

Where there is inadequate ventilation or the amplifier is being driven hard such that the internal components
are getting hotter than they are designed to run then the internal heat monitoring sensor will signal the
amplifier to shut down, and remain shut down until the temperature returns to normal.
The flashing red HEAT light indicates that the amplifier is operating at a temperature that exceeds its safe
operating limit. The amplifier is automatically shut down and the rear heat sink temperature is displayed in
flashing numbers on the front panel display.
S-400 Amplifier Owner's Manual 42
VTL