Vanguard® Medium FTS 370x – BCN COMM FAIL

Learn to troubleshoot a beacon communication failure (BCN COMM FAIL) on the Vanguard® Medium FTS 370x product series.


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Vanguard Medium FTS 370x Troubleshooting – Beacon Comm Failure


A beacon communication alarm indicates that the LED flash head is not communicating with its connected controller. The issues could be power, programming, bad wiring connections or a potential board issue.


Verify the Alarm Condition


  • Verify the alarm by checking the status on the main display screen.
  • Look for fully illuminated day, night and comm alarm LEDs.


Troubleshooting Step 1


Verify input voltage is in the correct range. Check the manufacturer’s serial label to verify correct input.

  • 120-240 VAC
  • +/- 24 VDC
  • +/- 48 VDC


If readings are incorrect, check the voltage at the source. Also verify that the internal breaker is not tripped.


  • If fuses are present, drop the assembly down to remove power from the source before servicing the fuse block.
  • Locate the size access flap.
  • Open the flap and pop out the F1 and F2 fuses for testing/replacement.


Troubleshooting Step 2


Check the main display to see if the power line communication (PLC) status LED (LED 15) is flashing red.


  • If the PLC LED does not flash, replace is PCB1 display board.
  • If the LED flashes proceed to the binding procedure.


Troubleshooting Step 3


Binding simplifies installations and board replacements by allowing each controller to find its external components (flash head and marker tier).


It replaces the need for configuration jumpers and dipswitches.


Binding assigns LED system communication—2-way communications transmitted through the same cable that feeds power to the tower lights at TB2.


Complete this process after every installation and if a flash head, display or marker controller board is replaced.


If multiple controllers are onsite, complete this process for each once. Verify only 1 controller is turned on at a time, powering down the other controllers.


  • On the display board, press enter 1 time.
  • Scroll down to “local tower config” and press enter.
  • Scroll down to “bind tower” and press enter.
  • Verify only 1 controller (power down additional controllers) is on and press enter.
  • Test the DC voltage on disabled systems on TB2. Press enter only once the voltage is below 5 VDC.
  • Wait until all components have been discovered (about 30 seconds).
  • Once the installed components are found, press enter to complete the process.
  • Repeat the process for additional controllers, one at a time.
  • If the process cannot locate the tower components or you see a bind alarm, select unbind tower and start over.
  • Proceed to the next step if you cannot bind the system. There may be an output voltage issue.
  • If the status on the display screen indicates OK, the issue is resolved and the alarm cleared.


Troubleshooting Step 4


If the display reflects a low DC notification, the controller isn’t providing enough voltage to operate the tower lights and PLC circuit.


Check the blue power LED, an indicator of full system voltage. Turn off the internal breaker and wait 5-10 seconds for power to discharge.


Don’t rely solely on the indicator for voltage testing. Use a voltmeter before servicing equipment.


With the power off, check these points for proper wire termination:

  • TB2 (SC 370 flash head cable connection)
  • P4 on PCB2 surge board (60 VDC output to TB2)
  • P3 on PCB2 surge board (60 VDC input from power supply)


Turn the system on and check for ~58 VDC on TB2.


  • If the power voltage is not in the correct range, power the system off.
  • Wait for the power to discharge before removing the red and black wires on TB2
  • Turn the controller back on.
  • Retest for ~58 VDC.


If the voltage returned to normal, suspect damage on the tower, such as a short on the flash head cable or poor wiring terminations in the flash head or marker j-box.


If the voltage did not return to the normal range:

  • Turn the controller off
  • Wait until TB2 is below 5 VDC
  • Remove P3 from the surge board.
  • Turn the controller on
  • Test for ~58 VDC on P3 pins 1 and 4
  • If you do not see ~58 VDC, replace the controller’s power supply.
  • If the voltage did return, replace the PCB2 surge board.


Troubleshooting Step 5


Check the PLC percentage. This illustrates how well or how fast the controller, flash head and mark junction box communicate. It helps determine is there are issues with the flash head’s core board or if the flash head is located near a high RF source, causing intermittent comm failures.


  • Scroll down to factory diagnostics and press enter.
  • If prompted for a password, use the up and down buttons to input the following: up, down, up, down, up, up.


After completing these steps, the system should operate normally. If alarms remain, reboot all equipment and verify the alarm condition.


If the percentage shown is below 40-50%, Ccontact Tech Support to run through additional diagnostics  (1.800.821.5825).

in Vanguard Medium