[pingoui]

Hello,
firstly I'd like to tell hello to everyone cause this is my first topic on this forum.
I was using cc3d on my quad for about a month and yesterday it stopped working.  When i plug my lipo there is only green light (but it lights not so bright as always). But when I plug it via USB to computer there is also a blue light and I can configure all by the computer.
Is there a problem with my power connections on quad?

[TheOtherCliff]

Maybe your BEC is not providing enough voltage.  Crash damage?

Maybe measure the voltage going into the CC3D.

Does it have a separate BEC or does it use the BECs built into the ESCs?

[pingoui]

So i've checked it, I get 5V from every BEC (BEC are built in ESC). What's interesting: when I connect only BEC with ESC the green light is really weak but when I plug my receiver it gets more bright but it seems that it's blinking really fast.

When the board is connected via USB i can configure all the motors properly..

[TheOtherCliff]

I would buy a CC3D and get it coming in the post if flying is more important than the $15 or so for an exact replacement.  Non-EVO (does not have DSM receiver connections?), full sized CC3Ds are $10 shipped on eBay.

Plug in the CC3D with the battery and no USB and let it sit for 10 minutes.  Does anything get hot anywhere?  ESC, component on the CC3D?  One ESC might get a little warm, but not hot.  If any tiny component on CC3D gets surprisingly hot, it may indicate a problem area.

I would try one more thing and then buy a new CC3D if that doesn't fix it.

Plug in USB and do File -> Export UAV Settings.  This saves your current settings to a file.  Save the file in a place you can find it. 

Then do System -> Halt
and Erase Settings when it becomes active after Halt.  Follow instructions.

Then test if there is a difference in the LED when booting from battery vs. booting from USB.

Finally, do File -> Import UAV Settings to put your settings back the way they were and see if it works.

Keep this file.  You can import it into a new CC3D, do sensor calibrations, and fly, rather than doing full setup.

Chances are that there is crash damage on the CC3D that causes this.  This particular issue sounds like it is caused by bad connection or component going from ESC/servo connector to internal 3.3V voltage regulator.  It could be fixed if you can read a schematic and do very tiny soldering, but buying a CC3D is a lot easier.

[pingoui]

Thanks for your reply. Unfortunatelly, after 10 minutes (and after 20 minutes) nothing got hot on the board

I went through your instructions and they didn't help me either. It seems that all I can do is buying a new FC.

[TheOtherCliff]

So the LED was still dim after the Erase Settings (and before the Import Settings)?

My CC3D has 2 LEDs.  One stays on all the time and the other blinks.

You might consider doing the Manual Rescue (search the wiki) procedure to flash the firmware again before replacing the CC3D.

[pingoui]

Yes, the green light is still on (but when only Lipo is connected it lights really weak), the blue LED appears only when board is connected via USB..

[TheOtherCliff]

For at test, I suggest you try disconnecting all but ESC/BEC #1 so that you are only getting 5V CC3D power from it.  See if the LEDs act the same that way.  Then try it with just ESC/BEC #2.  There is a chance that you have a bad ESC/BEC doing strange things to the battery power, but it would probably only be one ESC/BEC.  This will disconnect the bad ESC/BEC for a test if that is the case.

If it does it with default settings (i.e. after Erase Settings) and you have re-flashed the firmware and you have verified that you have clean (Linear BECs ?are? clean) 5V power going into the FC at the ESC servo connection (measured while connected) then I see no conclusion other than you have bad hardware.  The fix would be easy if you can solder tiny stuff.