Information subject to change
96-8005353_02-17-2022
8504 OPERATOR’S MANUAL – SECTION 4
10
4
Amplifier Operation
4.1
Front-Panel Controls and Indicators
This section provides an overview of Front-Panel
controls and indicators found on the 8504. Refer fo
Figure 4.1
for component locations.
4.1.1 Standby-Run Switch
The Standby-Run switch controls the power to the
amplifier’s high-voltage transformers.
Switch to
the Run position (right) to energize the ampli
-
fier. Switch to the Standby position (left) to
remove power from the high-voltage transform-
ers and place the amplifier in Standby mode.
4.1.2 Run/Standby Indicator
Run mode:
The indicator will be lit solid green.
The amplifier’s high-voltage transformers are ener
-
gized and the unit will amplify the input signal.
Standby mode: The indicator will be lit solid am
-
ber. The amplifier will be placed in Standby when
one of the following conditions occurs:
1.
High/Low Line error
2.
Overtemp condition
3. Fault condition
4.
The user sets the front-panel Standby-Run
switch to the Standby (left) position.
In Standby mode, the amplifier’s low-voltage trans
-
former is energized but the high-voltage transform
-
ers are not.
Figure 4.1 – Front Panel Controls and Indicators
To release the amplifier from Standby mode:
1.
High/Low Line error:
Clear the over- or un-
der-voltage condition. The amplifier will resume
operation when the input voltage is brought
within the operating range of the amplifier.
2.
Overtemp condition:
Remove the input signal
from the amplifier and leave the amplifier with
the Standby-Run switch in the Run position
and with the fans operating to cool the ampli
-
fier. When the amplifier’s internal temperature
drops to less than 100°C, the amplifier will
resume operation.
3.
Fault condition:
Turn the front-panel Standby-
Run switch to Standby and then back to Run to
reset the amplifier. If the fault condition recurrs
or does not clear, the amplifier may require ser
-
vicing. See the
Troubleshooting
section for
more information.
4.
Standby-Run switch pressed:
When the
amplifier is operating (Run mode), setting the
front-panel Standby-Run switch to the Standby
position (left) will place the amplifier in Standby
mode. Set the switch to Run (right) 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 lever greater than 0.5V, the Signal/Overload
indicator will light solid green.
