Power distribution board problems

[Baldwin Robotic]

Our power distribution board doesn't light up the 5 volt light. We tested the voltage and it wasn't reading 5 volts either.

Dose this mean we have a bad/broken board?

[F22Rapture]

Possibly. Where were you testing the voltage? At the connector, or at the wire?

[Dale]

Could be a bad power distribution board or it could be something is shorting out the 5v line. Make sure there's no metal flakes inside the connector and that nothing is connected to 5v when you measure it. Once that's checked out if the problem persists it is probably a bad power distribution board.

[Wendy Holladay]

We had the same problem.Disconnect things one at a time and see which wire is the culprit

[Alan Anderson]

If the BAT and 6V LEDs are lit but the 5V LED is not, there are three reasonable possibilities.

The most common cause I've seen over the past few years is a sensor switch connected to the wrong Digital I/O pins, connecting the (-) pin to the 5V center pin instead of to the SIG pin on the other side. That shorts the 5V power, and the supply on the Digital Sidecar shuts down to protect the wiring. Disconnect everything from the Digital Sidecar and see if 5V comes back. Then reconnect things one at a time, and see if any of them causes it to fail. If you find the offending circuit, track down what's wrong with it.

The second likely cause is a bit of metallic debris among the DIO pins, also shorting 5V to (-) and causing the supply to shut down. With everything unplugged, use a strong flashlight to inspect the pins for anything that might be a problem.

The remaining possibility is a faulty Digital Sidecar. After you've eliminated the other options, then replacing it is a good thing to do.

[edit]Whoops, I misread which board was under consideration. I think my advice is still good, just not in this context.[/edit]

[toastnbacon]

When in doubt, switch it out! I think that's the best way to figure out what's going wrong. If a new one works, mark the other as second rate and move on.

[Alan Anderson]

On the other hand, if faulty wiring is to blame, you might just fry every sidecar you install before you find the real problem. And since you have to undo all the connections anyway in order to swap them, you might as well take advantage of the opportunity to do some simple and straightforward troubleshooting.

[Mark McLeod]

Originally Posted by Baldwin Robotic

Our power distribution board doesn't light up the 5 volt light.

Sounds like he's talking about the camera 5v connection, rather than the Digital sidecar.

If you are talking about the 5v wago (normally power for the camera), then if you aren't getting power from it, it has probably blown it's fuse.
Of course you can get another 12v-to-5v converter and just power the camera through it off a regular 12v output.
There's nothing real special about the 5v power on the Power Distribution board.

But you do want to figure out why it blew before you do it again.

[jwallace15]

Originally Posted by Wendy Holladay

We had the same problem.Disconnect things one at a time and see which wire is the culprit

We too had the same problem with two PD boards. On one the 5 volt camera output didn't work, and on the other the 24 volt output (for the cRIO) didn't work.

If you want to look at the schematic for the PD board, go here, click "Power Distribution Board", then click "Power Distribution Board Circuit Design". Thank you 3992 for the schematic!

Hope this helps,

[Al Skierkiewicz]

There are a few things that can go wrong on the PD. Most are due to abuse. A hard drop can shake one of the larger components loose from the board or a short on one of the power supply lines can cause the current limit device to fail. You can repair the board under
R65 M. Devices may be repaired, provided the performance and specifications of the component after the repair are identical to those before the repair.
Be prepared that the components are surface mount and that requires a little experience to repair and replace. It is also possible that metallic debris has entered the PD and it needs to be cleaned. The PD is easy to open when it is not on the robot.