25
Maintenance
Description, Specifications, Installation, and Service Manual
Federal Signal
www.fedsig.com
Replacing the Driver
To determine if a driver is defective, refer to the procedure outlined in the installation
instructions for the amplifier control unit or remove the speaker circuit from the terminal
block and measure the impedance of the circuit. The impedance of each 400 W cell of
the siren will measure approximately 4.5 ohms. If the reading is higher (9 ohms), one
driver is defective. If the circuit is open, multiple drivers are defective, or a wire has been
severed. The impedance of a single driver should be 2.25 ohms.
To determine the location of the defective driver, see “Figure 6 Driver Connections” on
page 20 and “Figure 7 MOD6032B Driver Connections” on page 21.
To replace a defective driver:
1. Remove the four hex head 1/4-inch mounting bolts holding the inspection plate. Make
sure the flat washer and split washer are not misplaced. Note the color and location
of the wires going to the driver.
2. Remove the wire from the terminals on the driver.
3. Remove the driver by turning it counterclockwise.
4. Add a new driver by turning it clockwise.
5. Make sure that the male threads are greased.
6. Reconnect the wires as previously noted.
