Oh ... you might be onto something there Norbert.
Originally I understood from CarbonCore that I would not need to supply the ESCs with a separate 5V feed (eg. from a separate regulator or the like) as the flight controller would do that for me. I thereby assumed that the ESCs needed to be fed 5V from the flight controller in order to operate – something which I've seen on many other ESCs before.
I then tried and failed to get the motors to start when connected to the AQ, which I assumed was because of the gap in the middle track as shown in your diagram, so I bridged them all ... but the motors still didn't run. I then discovered that no PWM would be sent to the motors until the AQ was 'armed' by holding the rudder stick to the right. All the motors then worked fine and I assumed that was that.
However I bought a servo tester over the weekend, and lo-and-behold, with the red wire of one of the original ESCs DISCONNECTED, the ESC works fine, meaning I've been pushing 5V into the ESCs the whole time, without realising they didn't need it
I had even measured between the ESC red wire and ground to see if it had an internal BEC, and it read 0V, so I assumed I was doing the right thing by giving it 5V.
Do you think this would have caused so many of the ESCs to fail? If 5V isn't coming out of the red wire, I'm wondering whether it's actually connected internally to the ESC at all ...? I've attached a photo of the ESC that smoked during my first take-off attempts showing one of the FETs with lots of charring around it. I guess it's hard to say why the additional 5V would have caused the FETs to fail?
If this was the cause of the ESCs failing, I'm now feeling slightly stupid for buying a whole new set of ESCs
Many thanks for the guidance guys
David