96-8005549_3-18-21
Information subject to change
13
8508 OPERATOR’S MANUAL – SECTION 4
cases where the amplifier’s transformers have
overheated, up to15 minutes of cooling time
may be required before the amplifier can re-
sume operation. See the
Overtemp Indicator
topic in this section for more information.
3.
Fault condition:
Press the front-panel power
switch to reset the amplifier. If the fault condi-
tion recurrs or does not clear, the amplifier may
require servicing. See the
Troubleshooting
section for more information.
4.
Power switch pressed:
When the amplifier is
operating (Run mode), pressing the front-panel
power switch will place the amplifier in Standby
mode. Press the power switch again to release
the amplifier from Standby and return the am-
plifier to Run mode.
4.1.3 Signal/Overload Indicator
Signal Presence:
When an input signal is pre-
sented at an active signal input on the amplifier
at a level greater than 0.5V, the Signal/Overload
indicator will light solid green.
Overload (clipping):
The indicator will flash amber
intermittantly. When the indicator flashes amber, this
indicates that the output of the system could not fol-
low 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 when the
amplifier’s rear panel breaker is off or tripped. It
can also occur when the AC supply voltage to the
amplifier is too high or too low.
To remove the amplifier from Standby, the AC
mains voltage must be brought to within the opti-
mal range. Check the amplifier back panel breaker
and reset or turn the breaker on, if needed. If the
error does not clear, check the voltage from the AC
mains. Once the fault condition has been cleared,
the amplifier 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
amplifier may require servicing. See the
Trouble
-
shooting
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
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 amplifier fans are running
and then remove the input signal from the amplifier.
Allow the fans to run until the amplifier automatically
returns to Run mode. See the
Troubleshooting
section for information on identifying 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 power switch (off, then on) to
reset the amplifier. If the fault condition recurrs or
does not clear, the amplifier may require servicing.
See the
Troubleshooting
section for more infor
-
mation.
4.1.7 Emergency Stop Button
The Emergency Stop button controls the power to
the amplifier. Place in the ON position (not de-
pressed) to energize the amplifier. Switch to the
OFF position (depressed) to remove power from
the unit.
Summary of Contents for 8500 Series
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