UltraVoice Manual - Alerting & Notification

7.2 General Maintenance
A. Driver Replacement/Inspection
Each amplifier drives four 100-Watt
speakers.
To measure the resistance of a given
speaker set, proceed as follows:
1. Set an ohmmeter to its low
resistance range, and hold the
ohmmeter probes to the outputs
on the terminal strip (JP21-28)
(at the bottom of the system
mother board).
2. Observe the DC resistance of the
speakers. Normal DC resistance
of a speaker set of 4 drivers is
approximately 4.5 ohms. A DC
resistance measurement of less
than 3.5 ohms indicates that one
or both of the speakers is
probably shorted. A reading of
approximately 9 ohms or more
indicates that at least one of the
speakers in the set is open; a
reading of infinity indicates that
both speaker sets are open.
3. If a resistance is abnormal,
perform resistance checks on
each speaker individually at the
speaker array. Refer to the signal
connections section for speaker
locations. Each individual driver
is 4.5 ohms.
4. To replace a defective driver,
remove the four (4) hex head 1/4inch
mounting bolts that are
holding the inspection plate.
Make sure the flat washers and
split washers are not misplaced.
Federal Signal UltraVoice
Installation and Operation Manual
MAINTENANCE
60
Note the color and location of the
wires going to the driver.
Remove the driver by turning it
counterclockwise. Make sure that
the male threads are lightly
greased, then install the new
driver. Reconnect the wires as
previously noted. Reinstall the
inspection plate. Repeat
resistance check above.
5. Test the siren to verify the driver
has been properly installed.
B. Signal Operational Check
1. When checking for proper control
module output, unplug the
terminal strip connectors to the
speakers (at the bottom of the
system motherboard) to eliminate
output from the speaker array.
2. Activate each of the signals and
observe the signal indicators on
the control module and the
amplifiers.
3. If desired, an oscilloscope or
digital multi-meter (DMM) can be
connected to the amplifier
module output terminal strip to
observe the amplifier output. This
output should be at least 67 VRMS
during a signal. To limit sound
output, plug in one amplifier
terminal strip connector at a time
during this test.
4. Plug all of the amplifier terminal
strip connectors to enable
amplifier outputs.