[Que]

I was flying, crashed, and now cc3d no longer powers by battery. It will however power up when plugged into usb, and when I plug the battery in at this point every thing works as it should...I.E. ESCs work, transmitter works. Unplug usb and just plug in battery...nothing

[hwh]

Have you checked with a meter and made sure whatever powers the cc3d from battery is still putting out 5v and the wires to the cc3d are still good and hooked up?   Usually it would be a BEC on one of the ESCs or a separate BEC on a PDB and power would normally be put into the cc3d on one of the servo connectors.

If your receiver is powered off the cc3d is it getting power?  If it is the most likely failure would be the power isolation diode on the cc3d.

[Que]

There is a good chance that I am doing this wrong...but when I connect the leads from the MM to the - + on the ESC plug the V drops down to around 3v and the ESC gets hot.

[Que]

Receiver is not getting power from the CCD as it should. The PDB has no BECs. Those are on the ESCs. Hope I have this so it is understandable as I am still trying to learn this stuff. lol

[TheOtherCliff]

If the ESC gets hot when you connect the leads then you either are shorting the + and - together at the connector or you have the MM set to amps or you have the MM + lead plugged in the 20a (etc) connection which is ONLY to be used when you have it set to 20a (etc).

You must set the MM to something like 20v and plug the leads in the - and the normal (not 20a) +.

[Que]

DOH! I got it now...I don't use a MM very often and always have to go and look on youtube for info each time I do use it. Soooooo...The voltage coming from the ESC plug is like 5.15 to 4.99. I'm getting different readings depending on which plug I check. Is that normal?

[Que]

I soldered everything to a new PDB and now the power light comes on but not the status light or RX. I tried soldering the CC3D directly to the PDB but it still doesn't work the way it should.

[TheOtherCliff]

Each ESC has a voltage regulator (BEC) in it.  Manufacturing tolerances make a spread of voltages that you describe and that range is normal, but if all are plugged in, then the highest voltage will override the others and actually the FC/Rx power will be coming from that ESC/BEC and it will get warmer than the others.

So ... flight battery (12v) is plugged into ESC/BEC which reduces the voltage to 5v and that is what powers the FC.  The Rx gets 5v power via the direct internal connection to the FC 5v.  The FC internally regulates this 5v down to 3.3v (most receivers do too), but you don't need to know about that (unless you need it for a DSM satellite Rx which needs 3.3v).

If you or someone you know can do tiny soldering, you can replace the blown diode that is probably causing this (or just short that specific connection out with a solder bridge).  For most people, even those that can fix it, it is better to just buy a new CC3D for $8 or so.  It would probably cost you $5 (mostly shipping) to get the part, and there is a change that wouldn't fix it...

Here is one on eBay for $8 shipped.  Vertical connector pins.  I have not bought from this seller.
http://www.ebay.com/itm/CC3D-Openpilot-Self-stabilizing-Flight-Controller-32Bit-for-Multirotor-QAV250-LO/162228443444

[Que]

Thank you Cliff for the info. I wish I had found that seller yesterday when I was looking for a new cc3d. the one I purchased cost me a few dollars more than that.
 Eh...hard to come by easy to go. lol
Thanks again and also to HWH.