[I_drone_about_drones]

I've built a few Quads with cc3ds before so I know them quite well.
The quad I'm working on now is really bugging me. I built the quad, tuned it and all was fine. I crashed into a tree, a prop got bent and then it hit an ESC. The ESC was broken so I soldered another one on, Quite normal so far (I hope). I plugged in a battery, and nothing happened. I cannot figure it out because when I check the quad with a multimeter everything seems normal. As I was checking it I accidentally touched together the ground and the signal at the same time on one of the ESCs. Two ESCs(not the one I was touching with the multimeter), and the flight controller turned on. As soon as I removed the multimeter (stopping the connection) everything stopped. I tried running the quad through the vehicle setup, but when I start ESC calibration everything goes haywire. Normally I get synchronized beeps but now I get some beeps from one ESC then another, then two at a time, then they stop, and sometimes the motors go to full power. It's different every time. I have tried to the best of my ability to fix this quad, but nothing seems to work. It's built out of old parts so I don't mind if I have to dump it (Although I do want to get it working). Don't worry if you can't help me, but all help would be greatly appriciated. If you need more information, just ask.

[TheOtherCliff]

It sounds like you have a broken power system.  Perhaps a crack in your PDB (power distribution board).  Try flexing things with the battery plugged in to see what makes it change.

Another test I would make is to set a meter to the volts scale and connect it from battery minus to ESC minus on an ESC that shows a problem.  That should be a straight wire and thus have 0 volts across it.  If you ever see voltage showing, you have found a problem and can narrow it down.  If no problem found, try battery plus to ESC plus.

What powers your CC3D?  The ESC BECs or a stand alone BEC or a BEC built into a PDB?  BEC built into the PDB could have some crash damage.

The CC3D could also be damaged.  What happens to the CC3D LED when it goes crazy?

I assume you don't use any metal mounting hardware (screws, nuts, washers, standoffs) for the CC3D.

[I_drone_about_drones]

Maybe I Need add some more information.
The PDB is definitely working as All the ESCs are getting the correct voltage.
The BEC is working as I checked it with the multimeter and also the vtx and the FPV camera is working.
The CC3D is definitely getting 5V as I checked the voltage right on the CC3D.
When I have the FC plugged into the computer, The CC3D lights seem normal.
My best guess is that the CC3D is fried, although would it still work when you plug it into a Computer.
One question, Are the beeps that the ESCs make When the battery is plugged in controlled by the FC, Or are they ESC controlled. Plane ESCs seem to beep as soon as you plug in the battery and they don't have a FC.

[TheOtherCliff]

From what you said, sometimes it works and sometimes not...  So do you know that you tested these things when it was failing? 

Plug battery in and check for voltage (red wire vs black wire) everywhere, at each ESC, at FC...

ESCs play "startup beeps" if they see a good (low = motor off) signal when they are first powered on (and if signal goes away and comes back).

Some ESCs beep once each few seconds if they get power, but don't have a signal (like FC without power).

ESCs are silent after the startup beeps if they are getting a good signal, even a "low enough to stop motor" signal.

[I_drone_about_drones]

The Quad worked until I soldered a new ESC on.
I tested everything after I soldered the new ESC on and everything was normal. I have another CC3D that I will try connecting up.
We will see have to see how the other CC3D behaves.

[I_drone_about_drones]

Okay, I've connected the other CC3D up and everything is fine. I wonder what was wrong with the other board. It worked when I plugged it into a computer and when I connected the ground and the signal together.

 I think it could have been a bad connection somewhere, although I checked everywhere with the mulitimeter. Can soldering a new ESC on Damage the board? Is the board I have removed still fine? Maybe I'll find out someday.