96-8005353_02-17-2022
Information subject to change
11
8504 OPERATOR’S MANUAL – SECTION 4
Overload (clipping):
The indicator will flash
amber intermittently. When the indicator flashes
amber, this indicates that the output of the system
could not follow the input signal due to voltage
or current limits. The amber Overload indicator
will begin flashing when distortion is greater than
0.1%.
4.1.4 High/Low Line Indicator
This amber indicator will illuminate, and the ampli
-
fier will be placed in Standby if the detected AC
mains voltage is outside of the operable range of
the amplifier (±10%). This can occur if the ampli
-
fier’s back-panel breaker is not in the on position
(left), or if the AC supply into the amplifier is higher
or lower than the operable range.
To remove the amplifier from Standby, the AC
mains must be brought to within the optimal range.
Once the fault condition has been cleared, the am
-
plifier will return automatically to Run mode. If the
High/Low Line indicator does not turn off or if the
amplifier does not return from Standby, the ampli
-
fier may require servicing. See the
Troubleshoot
-
ing
section for more information.
4.1.5 Overtemp Indicator
The amplifier monitors the temperature inside the
high-voltage transformers and in the output stage
heat sinks. The amber Overtemp indicator will light
and the amplifier will be placed in Standby mode
Figure 4.2 – Back Panel Controls and Connectors
when the temperature sensors detect a condition
that would damage the amplifier. If the Overtemp
pulse is extremely short, as in the case of defec
-
tive wiring or switches, this indicator may be lit too
briefly to observe.
To remove the amplifier from Standby and return
it to normal operation after an Overtemp fault has
occurred, make sure the Standby-Run switch
is in the Run position and the amplifier fans are
running, and then remove the input signal from
the amplifier. Allow the fans to run until the ampli
-
fier automatically returns to Run mode. See the
Troubleshooting
section for information on iden-
tifying and correcting the cause of an Overtemp
fault condition.
4.1.6 Fault Indicator
The red Fault indicator will light and the amplifier
will be placed in Standby under two conditions:
1.
High frequency oscillation is causing high
shoot-through current.
2.
An output transistor has shorted, causing the
output fault condition.
Cycle the front-panel Standby-Run switch (Stand
-
by, then Run) to reset the amplifier. If the fault
condition recurrs or does not clear, the amplifier
may require servicing. See the
Troubleshooting
section for more information.
