12v and 24v led not lighting up

[njd231]

my power distributor 12v and 24v led lights stop lighting up all of a sudden. One second they worked, the next they didn't. the last thing i did was deploy C++ example on the getting started with C++ pdf; then it went out?

How do i fix this problem?

[Alan Anderson]

Make sure your battery isn't dead. If it goes below about 5 volts, those power supplies probably won't be able to function.

[jp1247]

Even at around 8 volts they start to stop working you're power distribution board might have also just quit, especially if its an older one, it has happened to my team before.

[njd231]

Everything still works except the VC (the port for the small black piece that goes to the cRIO) isn't working and the RSL on the DO isn't working.

[jp1247]

I would say just use a different PD, but this is your rookie year, good luck by the way. Put a new battery on it, and meter the different outputs, and see what you get.

[tsaksa]

Ditto on trying another battery, or at least checking the voltage while it is under load.

But you may want to also try pulling all of the breakers, and disconnecting the 5V and 24V power connections, such as connections to the CRIO. It is possible that you have something pulling more current than it should in standby mode and that may be helping to drain your battery faster than you suspect.

If you get a reading of about 12 volts on the battery and the lights do not come on with the CRIO and similar devices disconnected than you probably have a problem with the power distribution board. If the voltage is well below 12 volts than at least part of your problem is the battery. And, if you unplug the CRIO and the light suddenly comes on you need to check your wiring to the CRIO or the CRIO itself.

[jp1247]

On another note, this season, on last season's bot, we discovered that a couple of the outputs(40amp and 20/30 amp) were only putting out at around 8 volts, and would drop to 5 with any load, we were using the LED ring when we discovered it. We're going to just use the new PD, but you obviously can't.

[njd231]

I read the voltage going into the power distribution board its 12.5v. Do i need a new PD?

[jp1247]

Between the two lugs? No that is a fully charged battery... Try a 40 amp slot (with a breaker in it) a 30 amp slot(with a breaker in it) you 12 volt output, 24 volt output, 5v ouput etc.

[tsaksa]

Originally Posted by njd231

I read the voltage going into the power distribution board its 12.5v. Do i need a new PD?

Do you have the CRIO and similar connector outputs unplugged or disconnected from the PD board? I still think you still need to completely eliminate the possibility of a short on something you are driving. A short elsewhere may make it look like you have a bad PD board when the problem is actually in the wiring. Also, are you completely sure that you have the positive voltage going to the correct lug of the PD board? Check that with a meter as well. Even a battery could have been accidentally wired so that + voltage goes to the wrong terminal. The students are often quite eager to put things together and do not always realize that the polarity matters here.

When I have a problem with something like this I start by not trusting anything and recheck the simplest things.

[Al Skierkiewicz]

Originally Posted by jp1247

Even at around 8 volts they start to stop working you're power distribution board might have also just quit, especially if its an older one, it has happened to my team before.

Not quite right, the Crio when it sense battery is at 5.5 volts will inhibit all output. The power supplies will stop functioning at 4.5 volts.

Deploying code will not cause the power supply to malfunction. However, plugging into the Crio port can and often does disturb the power wiring. My first suggestion is to remove the Crio connector from the PD and turn the power on. If the 24 volt LED comes on, check the Crio power wiring for stray strands or mis-wiring.