Hi,

I just bought an ArduCopter Kit a few weeks ago and finally assembled it. Now I have some issues communicating with the board via the APM Planner. 

Here is a bit of history of my problem:

1. I was able to connect, download and configure the software using APM Planner

2. I setup the RC, ESCs and everything else successfully

3. I've assembled the kit completely and was able to arm and control my servos fine

4. After swapping the ESC connections to configure the correct direction for all motors. Reconnected to battery and everything worked well.

5. Installed the propellers and connected the batteries. Some ESCs start beeping and the servos were twitching

6. After that I could not re-arm my ESCs but the RX was working since I've seen the send blinking

7. Disconnected the the ESCs and battery and tried to re-program the board. Then I realized i cannot connect anymore.

Here is exactly the symptom i got now:

• If I start the terminal, i get the following line "Opened com port" which means that my USB connection is established but the board does not reply. I see the Tx Blinking each time i type something in the terminal so it seems that the software is not running or nothing comes back.Usually I would expect to get back the APM version and the prompt.
• Also trying to update the  firmware, I can see the APM Planner trying to query for the APM version and after that it fails with the error - "Cant detect your APM version. Please check your cabling". 

Other facts:

1. To prove the the Rx works I short the Rx and Tx  pins I can echo back everything I am typing so that makes me think that everything is fine with the USB Cable and the FTDI cip.
2. I have checked for cold soldering again i think everything is fine.
3. For a week I put this thing on a side and started working again on it today. Interestingly enough I could connect fine once, was even able to re-load the latest ArduCopter software and played with the terminal for a while. After that I tried to get some Flight Data, flipped the CLI switch to FLY mode and connected. It connected well, the MavLink dialog box started to receive data but that's where is died again. No data was received and I am back to square 1.. Not data comes back form the APM...

Can somebody help me figure out what's wrong? There is nothing more upsetting than having everything work for 10 minutes and then stop... 

I want to mention that I've tried connecting with different USB cables, have no driver or connectivity problem as I was able to communicate well with this board initially. 

Does this point to a bootloader issue? 

Is there anything else i should test, try, measure to provide more insight? Any thoughts?

Thank you very much for help,

Horia