Hello
I have had a problem with my drone for a while, I'll list the "symptoms":
- when I turn it on, I hear only the 3 initial beeps and not the two prolonged ones; from what I have read it means that it does not find the trottle signal (and therefore cannot start the arming phase)
- the drone does not arm, the motors do not start although the remote control tells me that it is connected to the drone and the r9m receiver has a green light.
- I don't see the telemetry from the viewer, before I saw it only when it was unarmed but now zero.
- I could not connect the drone to betaflight, I also tried with emuflight and bhel32, but nothing they do not see, it is not the fault of the pc port or the cable because I used various cables that I used even before and I also tried another one pc. (so I can't flash the FC or see what's going on).

to solve I tried to check all the doors of the ESc with the multimeter, looking first at all the doors between them and then with the battery source and everything is fine (I removed all the motor cables to do this test).
I have removed and resoldered all the cables of all the components from both the FC and the ESC.
In the FC there are the LEDs on and this makes me think that it is not burned, I am more worried about the ESC.

If you are not able to connect to BFC (betaflight configurator) then likely nothing is setup correctly. Let try to see if you connected first.

When you plug into USB, what device shows up in the device manager?

(02-Apr-2021, 08:56 AM)voodoo614 Wrote: If you are not able to connect to BFC (betaflight configurator) then likely nothing is setup correctly. Let try to see if you connected first.

When you plug into USB, what device shows up in the device manager?

I tried to see from a windows computer and in the list of connected devices it does not come out, it is as if it reloaded the window but I do not see it, on the FC there is the 3V led on

If windows is not even recognizing any device, then I would first check the USB cable or the port. Most commonly, you are using a charge only cable and not a data cable.

(02-Apr-2021, 04:08 PM)voodoo614 Wrote: If windows is not even recognizing any device, then I would first check the USB cable or the port. Most commonly, you are using a charge only cable and not a data cable.

I tried from the windows pc and it doesn't detect anything, I tried with the cable I usually used and it doesn't work (I tried on all ports).
From Mac I tried and I don't see anything, on betaflight with even different cables it doesn't detect anything. 
In both PCs when I connect, the 3V light on the FC lights up.

Is it 20mm stack?
26mm AIO ?

if FC with nothing solderee to it fails to connect,
start looking at deals page.

(02-Apr-2021, 04:44 PM)romangpro Wrote: Is it 20mm stack?
26mm AIO ?

if FC with nothing solderee to it fails to connect,
start looking at deals page.

it is a mamba f7 app, with a mamba f60 pro as ESC. 
cam, vtx, receiver, gps are currently connected.

do you think it burned?

(02-Apr-2021, 04:28 PM)gianlucafava Wrote: I tried from the windows pc and it doesn't detect anything, I tried with the cable I usually used and it doesn't work (I tried on all ports).
From Mac I tried and I don't see anything, on betaflight with even different cables it doesn't detect anything. 
In both PCs when I connect, the 3V light on the FC lights up.

I know that you keep on saying that you use different cable. But can you confirm that any one of these cable actually is a data cable? We have had people here say the same thing, that they tried many cables. But it turned out to be the cable in the end.

(02-Apr-2021, 05:44 PM)voodoo614 Wrote: I know that you keep on saying that you use different cable. But can you confirm that any one of these cable actually is a data cable? We have had people here say the same thing, that they tried many cables. But it turned out to be the cable in the end.

yes sure, I have this drone for about 4 months and to configure it or to change things / update it I always used a cable and to be sure I tried to connect it to the phone and check if it was also data and it is, it has not broken or things similar. I think it's not a cable or port problem but rather the drone

(02-Apr-2021, 06:09 PM)gianlucafava Wrote: yes sure, I have this drone for about 4 months and to configure it or to change things / update it I always used a cable and to be sure I tried to connect it to the phone and check if it was also data and it is, it has not broken or things similar. I think it's not a cable or port problem but rather the drone

Does sounds like your FC might just be bad. Does the MCU gets hot when you have the power plugged in for a bit?

(02-Apr-2021, 07:53 PM)voodoo614 Wrote: Does sounds like your FC might just be bad. Does the MCU gets hot when you have the power plugged in for a bit?

it overheats a lot, but it is something that it did from the beginning even as soon as it was bought in fact I hadn't noticed it until now.

 I know it's a bad index if it is burned

As I said before, unplug ESC and unsolder everything.

Examine pads closely for bridging. Make sure no little wire whisker or solder blob.

If it doesnt boot up and connect with USB by itself, need to buy new one.

(03-Apr-2021, 12:24 AM)romangpro Wrote: As I said before, unplug ESC and unsolder everything.

Examine pads closely for bridging. Make sure no little wire whisker or solder blob.

If it doesnt boot up and connect with USB by itself, need to buy new one.

then,
I took my ESC, removed all motor cables and power cord from it, and left it bare.

i checked all motor pads with the positive and negative of the power supply and they all gave me that there was power (and that's right from what i saw on yt).
then I checked the motor pads taken at 3 to 3 (checking the single outputs of each motor) and from what I saw they should not give current between them, they should be at zero; but to me ALL gave a passage of current all and 4 outputs of the motors.

the ESC on sight has no problems like burns so I don't understand ...

   
   

(03-Apr-2021, 05:21 PM)gianlucafava Wrote: then,
I took my ESC, removed all motor cables and power cord from it, and left it bare.

i checked all motor pads with the positive and negative of the power supply and they all gave me that there was power (and that's right from what i saw on yt).
then I checked the motor pads taken at 3 to 3 (checking the single outputs of each motor) and from what I saw they should not give current between them, they should be at zero; but to me ALL gave a passage of current all and 4 outputs of the motors.

the ESC on sight has no problems like burns so I don't understand ...

I think romangpro is asking you to inspect the FC. It is your FC that is having issue.

Anyways, overheated MCU as you mentioned before is pretty much a dead MCU. Any short circuit would have already destroyed any microcircuitry in the MCU.

(03-Apr-2021, 08:49 PM)gianlucafava Wrote: yes that's right, 
I think that's the problem too, but how can I check if the HR has problems

Not sure what you mean by HR? But you can check to see if the ground pin is shorted with the 3.3V in the MCU. Also look for solder bridge or burnt component on the FC.