cRIO won't turn on.

My team’s cRIO stopped turning on. When I turn it on, it simply buzzes. The Power and Status lights on the cRIO do not light up even though the lights on the power distribution board, digital side card, and various modules do.

What might the problem be?
Is there some permanent damage to the cRIO that I am not aware of?

I’ve spent hours trying to figure this out so I am open to any help that anybody is willing to offer.

Around when did it stop working? Did anything happen at that time?

Inspect the cRIO for metal shavings and the like; you may also want to try contacting NI’s helpline.

Also you should post a picture of your crio if you can, we can verify if it is wired correctly. As check to make sure the wires are not touching each other at the terminals, every year we run into that problem and I have to correct the student wiring. ::safety::

Check the connectors in the bottom of the cRIO where the modules go in.

Perhaps someone misaligned and forced a module in, thereby causing damage to the connectors at the bottom.

While the Crio is pretty bullet proof it is not indestructible. The first things to check is the +_24 volt LED on the PD. Is it lit and steady? If not, remove the connector from the PD and turn the robot on. If the LED is still not on and steady, the fault lies with the PD. If everything is OK, then, using a voltmeter, check the +24 volt input to the Crio for presence and polarity. Examine both ends for stray strands of wire. It is quite common for strands to wander and short to the other wire. If all of these test pass, then with power off, remove all of the modules and check for shavings, bent pins, or other obvious damage to the chassis. Power up with the modules removed and see if the Crio will start. If it does, turn it off, add one module and try again. You may have a bad module.
We are all assuming you have a known good, charged battery on the robot.
Let us know how things are going.

We had a problem with ours too. It seems that the ones in the 2011 parts pack have a defect that causes them to loose a part (probobly a fuse) inside after they are hit violently. If this is a new RIO (under one year, I believe) you can call in and take out a warranty on the part and receive a new one for no cost. If its older you may need to purchase a new one. Hope this helps.

Thank you for your help. The cRIO has suddenly started working again.
It stopped working yesterday (Feb. 7) around 6:30. After leaving it alone and coming back to it (around 3:30 today), it has started working–turning on–again.

While I am glad the cRIO is functioning again, since I don’t know what caused the problem in the first place, I will still post a photo later today when I have access to a decent resolution camera.

What do you mean by buzz? Was it a really high pitched whine, or a low pitched grumble?

it was a very low pitched grumble.
And sadly I must amend my last post. If I wait a long time before turning the cRIO on it works for a short period of time and then stops working abruptly; the Power/status lights turn off, and the cRIO begins to buzz/grumble again.

You are connected to the dedicated 24 volt power on the power distro correct? Did you try removing all the modules? This really sounds like a power problem.

I feel stupid.

After panicking for a while, another member of my team suggested that we change the battery. We did. The problem went away. Thank you for your help but I have found the source of the problem: the battery was out of charge.

That is good news considering the other possibility.

I’m still confused as to what was making the noise, but I’m glad it is resolved. Usually the supplies whine just barely in range of adult hearing when they are unhappy.

I haven’t opened one of the new four slot Crios. Could it be that there is a switching supply inside?

Yep, several. I was originally thinking about the PD side, but it could very well be a cRIO side switcher that is sleeping when it detects too little voltage, and periodically waking up to try again when the voltage trickles back up enough.

Just a theory though, I’d have to hear it.

Do we have any pictures or schematics of the new device?

Usually a severe hit is indication of metallic debris being knocked loose, not a component being knocked off. The conformal coating this year should dramatically improve immunity to this issue. Regarding warranty, FIRST has a 3-year warranty on parts, which includes advance replacement during the build season.

Also the note about the buzz is accurate. If it isn’t turning on but there is a buzz, that’s the power supply trying to turn on, but failing because voltage is too low. The switching frequency is in low enough that it creates a buzz. Always check your input voltage (and charge your batteries!)

Thanks Chris