I purchased a almost new phantom 4 drone that had fresh water damage. The drone would constantly beep in a constant fashion when turned on, no varying beeping pattern. It would not connect to a computer or the controller. First of all, I am a computer technician so I have repaired many computers, phones, tablets and other devices over the last 30 years that have had different degrees of water damage so I am familiar with all that and have gotten very good at that. I have disassembled the drone down to the boards, properly cleaned all components of any residue and reassembled. After reassembly the beeping has not changed, nor will it connect. I get a flicker on the motors when turned on and some lights on the motors (might still have a esc board damaged but the main concern to begin with is the connection). There are 2 other boards, the processor board under the heat sink and the main board on the vibration pad. I am not sure which one I should tackle first since I am not sure what controls which aspect of the drone. First, can anyone tell me what each of these boards control? And second, has anyone come up with a similar situation that I might be able to try? I have tried to find replacements for these boards but really don't want to just try and start replacing parts that might not help with the problem. Thanks for any help.