Vanguard® Medium FTS 370x Troubleshooting – Low DC

In this video from Flash University, we take a look at the voltage supply used to operate the tower lights. We will examine in detail what a “Low DC” message means and the appropriate steps to take to resolve any voltage issues in the system controller.



Vanguard Medium FTS 370x Troubleshooting – Low DC


Welcome to Flash University.


Let’s look at how to troubleshoot a low DC notification on a Vanguard 370 system.


If the status shows a low DC notification, the controller is not providing enough voltage to operate the tower lights and PLC circuits.


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


Never rely solely on the lamp for voltage testing. Use a voltmeter before servicing the 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 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.


Contact Tech Support for any additional issues.

in Vanguard Medium