Still thinking about a corrupt cable or shortcut. One try is worth to do: Plug out the USB cable from the processor board. It's the white connector on the left side of the processor board (picture in #16).
And try also to unplug the status LED on back of the copter.
I tried to provoke this behaviour but with no success. The next step after the short beep and the six blue lights on is to switxh on the LED below the motors. After that th flight contoller is booting and the boot-up sound will come.
The only thing I can imagine in this case is a bad battery or bad battery connection.
Do you have the possibility to measure the voltage with a mulimeter?
At green "1" should be alway 16V (full battery voltage, minimum 14V) no matter if it's on or off.
At condensator "2" should be only 16V if the copter is on.
View attachment 11973
Please be careful during measurement. Shortcut may cause fire or demage.
br HE
That's the problem. CPU cannot boot up without power supply. Now we have to find out, why 5V is missing. The ESCs have also their own 5V supply. That's why their blue LEDs going on.
Step-down-converter for 5V is TPS5450. There are two of it on the back side of the main board. I don't think, there is a fuse or so. The TPS5450 has Overcurrent limiting, overvoltage protection and thermal shutdown build in.
Do you have Real-Sense Module?
Can you unplug the Ultra-sonic sensor too?
Unplug all you can and try to boot again. Just to make sure that the problem not comes from outside the main board.
br HE
Hmm, I found another fuse, don't know for what it is. It is a white SMD part with a 'K' on it, near the Real-Sense connector on the back side of the main board.
View attachment 11992
But I think it is for the Real sense module. For all trhat goes outside the body they have a fuse: the camera, the ESCs and ..?.. the Real sense module.
br He
I do not have a Real sense, don't know. I cannot test this. The real sense should connected by a black cable that is plugged in the empty white connector at the picture in #26.
The cable looks like this:
View attachment 12009
The cable is always assembled no matter if a Real sense module is there or not to make it easier to install one. I have removed it because I will never install a RS module.
Please notice, that all cables, also the grey ones need to be proper twisted. This not only an optical thing, it is neccessary to decrease influences between cables and electronics. It's important if you will bring the stuff together back in the body.
br HE
Hi there! Did you resolve the problem?T
Thank you so much,
Anyway, the dron should start up event if this cable is corrupted. I think it must be a problem with the energy supply Steve Carr was talking about, the main board fuse does not get lighted when starting up...
Greetings,