Hi
It has been over a year since I have touched a CC3D flight controller so I am abit rusty on the specifics. We do have a guide here that might help. I cant remember if the CC3D will provide power to a reciever when plugged in via USB only, but I suspect that it will not so you need to connect battery power.
For the receiver not getting power:
- First measure the voltage coming from an ESC to confirm it is actually outputting 5V (also if all 4 ESC output power, you should disconnect the power from the other ESC so only one is sending power to your FC)
- Check the receiver power output has power on the receiver port (red and black wire)
- Make sure your receiver is connected correctly to the FC
- If receiver is getting power, but does now have any LED, maybe the receiver is faulty.