[SOLVED] Light cubes not working



Hey guys,

I just got the external light cubes and wired them up, but I can’t manage to get them working. Wires were soldered on exactly like the image provided by Brian (both black wires wired to the black/purple PWM wire, both red to the red/purple wire). I have the latest 30.0.3 software, and I can hit alt + i to get the lights on full power (as indicated on the dashboard), but the lights refuse to show any signs of life. Do you guys have any advice?

It’s the v2.8 board, so (according to the guide) there is no soldering or wire connection that needs to be done on the board itself, is this correct?

NEW PRODUCT- External Light Cube

I took a look at the OpenROV 2.8 Controller Board PWM & Environmental Sensors schematic for the PWM3 Connections to Wire Harness for External LEDs and you might want to make sure that there are solder jumpers at the following locations: R32, R73, and R74. Unfortunately you might have to remove the BBB to be able to see the area of the board where those jumpers are located.
If those solder jumpers are in place, then it might mean that the FET switch that is used to modulate the LEDs is not receiving a drive signal from the Arduino 2560 or heaven forbid the LED Cubes got wired up backwards during their manufacture.
Also, did you mean software version 30.0.3 and not 3.0.3?


I had a look, and all those jumpers have bridges on them. I used a volt meter, and there’s definitely 9V going through those wires when I’ve got the external lights switched on. I’ve wired up the lights individually to try and see if one of them was faulty, but neither are working.

Only explanation I can think of is that the light cubes are faulty or were wired backwards.

Solved it! Didn’t think when I looked at the volt meter, it was showing negative voltage!

The purple PWM wires were backwards from the factory… Crossed the wires and VOILA! LIGHT!


I am glad to hear that you were able to find and fix the issue. We apologize for the mistake in the harness. Just to make sure I have this correct for our internal noting and quality control purposes. When you are looking at the wiring harness pins 20 and 21 had the wire colors swapped?


Yes, that’s correct!


Thank you for the information. This was a defect in the wiring harness from the manufacturer. We strive to maintain the highest quality, but every now and then a mistake does slip through. We apologize for the hassle this created and are glad you were able to find and solve the problem. If there is anything else we can help you with, please let us know.


Hi Brian,
Thanks for the OpenROV DB-25 Cable Assembly Schematic, much appreciated.