Power Distribution Panel: No LEDs on when powered

Technical Electrical
1

Hello!

We recently dug our backup Power Distribution Panel out of storage to use with a new practice robot. I have been using it to power a RoboRIO, 4 TalonSRX, a VRM, and an OpenMesh router. I recently noticed that the LEDs on the PDP are no longer lighting up when power is applied and the PDP does not appear in the CAN Interface section of the RoboRIO web dashboard, but all devices are receiving power and I have noticed no other issues with the system. I have set CAN IDs for all four TalonSRX connected and the CAN wires appear properly plugged into the RoboRIO, each of the 3 CAN Connectors and the PDP. The jumper for the resistor is installed in the “ON” position. I check all of the fused installed and none are blown. I’m not sure if this PDP’s LEDs ever lit up when power was applied or that it ever appeared in the CAN Interface section of the RoboRIO web dashboard. Please let me know if you have any suggestions or need more information.

Thanks!
Benjamin

BTW, this is my first post; please let me know if there’s anything I should/shouldn’t include/do in the future!

2

The symptoms sound like the PDP CAN circuit board has been damaged.
You can open the cover and inspect the board-it’s right on top and easily visible.
Here’s an example of a damaged PDP circuit: https://www.chiefdelphi.com/forums/attachment.php?attachmentid=23681&d=1543085564

It won’t support CAN-based functions like current sensing, but it’ll still distribute 12v power just fine.

The PDP won’t be FRC legal, but will be otherwise okay for practice power and benchtop testing.

3

Thanks for the info, Mark. We’ll be using it on our practice bot, so that sounds like it will be okay. I’ll take a look under the cover and check for debris or damage next time I’m in the shop.

4

Concur this sounds exactly like dead smart circuitry. I saw this happen once when the PDP had been plugged in to the main power backwards.

1 Like
5

Exactly what @dydx said.

Once through lack of attention to detail, I powered the PDP with reverse polarity, and it killed the CAN circuitry, and made a loud clicking noise at first. When I fixed the polarity, the power will still output to all the outputs, but the CAN-BUS will be dead.

1 Like
6

I don’t know the full history of the PDP in question, however I did find it in a dusty crate where we throw extra electronics items, sooooo… I expect that is exactly what happened.