31
Installation and Maintenance Manual
Federal Signal
www.fedsig.com
Maintaining and Servicing the Allegiant
Reinstalling a PCB
To reinstall a PCB:
For ROC PCBs, gently snap the PCB to the reflector.
1. ROC boards must be connected as shown in Figure 10 to avoid overloading a
single connector. Install the assembly to the light bar and reconnect the harnesses.
2. Reinstall the dome. To prevent cross-threading the barrel nuts, back them
counterclockwise until you hear the click of the threads engaging, then tighten
them to 16-24 in-lb.
3. Reconnect power to the light bar.
Resetting the Controller
These instructions explain how to reset the Allegiant light bar after you install a
service replacement board or if the light heads operate erratically. For the light bar to
operate correctly, the controller stores information about which LED colors it controls.
Resetting the light bar controller may be necessary if you replace the controller board
or if the LEDs flash erratically. To scan the colors that are available at the end of the
reset cycle, the controller briefly flashes all LEDs simultaneously.
Be sure to perform the reset cycle on a vehicle with a well-charged battery. Failure to
do so may cause the light bar to flash or operate incorrectly.
The 21-inch Allegiant light bar has an integrated controller board and does not ever
need to rescan.
To reset the controller:
1. Remove the barrel nuts and lens from the light bar. (See Removing and Reinstalling
the Light Bar Lens on page 28.)
NOTE: If you are replacing the controller, ensure that power to the light bar is off, and
then disconnect all connectors to the controller. Install the new controller and re-
connect all cables to the controller board.
2. Connect the ROC board connectors to the controller.
3. Connect the Power and GND cables to the controller.
4. Connect the STT Cable to the controller if needed.
For Serial Models
5. Connect the CAT5 Cable to the controller.
For Discrete Models
5. Connect the 6-pin and 2-pin cables to the controller.
NOTE: Do not connect both discrete and CAT5 cables at the same time.
6. Verify that the light bar is working.
