3" quad. Hifion F7 AIO 45A. Apex1303.6. I've flown it maybe 30+ times.  

I was flying around parking lot at night. Some propwash. 
Plugged into phone Speedybee and changed PID.. upped the D.. changed vtx channel. Save.

Wont arm. Reports "rpmfilter". Then I realize, there is no ESC chime. 
The LED lights turn on, because it recognizes the radio. 

Come back home. Plug in. Betaflight shows nothing weird. 4K. DShot300. Bidir enabled.
Connect to BLHeli_Configuration. Read Setup. Nothing shows up.

There are NO ESC.
Yes, it is BLHeli_S and yes I am using right program.

probably its a bug, no signal or passtrough. i would try to flash the firmware fresh

I full erase flashed. No difference.
How can all 4 ESC be missing?

I guess its time to disassemble, and use multimeter. Very likely microcontrollers are getting shorted.

So strange that NO esc's appear!

Since the warning flag is RPMFILTER have you tried turning OFF bi-directional dshot in betaflight? If it was on, that is. (I don't know why that would make any difference as you were just flying, but since it's just one click I would try it out)

I don't understand why it would suddenly not work after flying and only changing PID and channel.

After desoldering first the LED, then the lowESR (it was crushed by canopy somehow)..
and finally desoldering all the motors... still no ESC found in BLHeli_Configurator.

I think I found the cause. There is a finger burning area - the vreg in upper right.



Can test to see if it happens in another board.
I have another Hifionrc F7 AIO.. uhmm.. I think its in one of my 4".. I'm not sure.

Also.. the BLHeli_S logs are not usefull.
Reading setup
sending cmd_DeviceInitFlash 0 0
received cmd_DeviceInitFlash ACK_D_GENERAL_ERROR 0 0,0,0,0
received cmd_DeviceInitFlash ACK_D_GENERAL_ERROR 0 0,0,0,0
ESC 1 read settings failed cmd_DeviceInitFlash ACK_D_GENERAL_ERROR
sending cmd_DeviceInitFlash 0 1
received cmd_DeviceInitFlash ACK_D_GENERAL_ERROR 0 0,0,0,0
received cmd_DeviceInitFlash ACK_D_GENERAL_ERROR 0 0,0,0,0
ESC 2 read settings failed cmd_DeviceInitFlash ACK_D_GENERAL_ERROR
sending cmd_DeviceInitFlash 0 2
received cmd_DeviceInitFlash ACK_D_GENERAL_ERROR 0 0,0,0,0
received cmd_DeviceInitFlash ACK_D_GENERAL_ERROR 0 0,0,0,0
ESC 3 read settings failed cmd_DeviceInitFlash ACK_D_GENERAL_ERROR
sending cmd_DeviceInitFlash 0 3
received cmd_DeviceInitFlash ACK_D_GENERAL_ERROR 0 0,0,0,0
received cmd_DeviceInitFlash ACK_D_GENERAL_ERROR 0 0,0,0,0
ESC 4 read settings failed cmd_DeviceInitFlash ACK_D_GENERAL_ERROR

Anybody know where to buy
8K910

its very likely the 3.3V LDO thats dead because LED work and Im getting 4.9V on 5V pads

(25-Aug-2021, 04:23 PM)romangpro Wrote: Anybody know where to buy
8K910

its very likely the 3.3V LDO thats dead because LED work and Im getting 4.9V on 5V pads

Turns out I'm a dumba%#$. It was the 5V circuit. 

Somehow magically it was not complete short.

After removing SMD marked "C", board works. I haven't tried flying it yet though.

Awesome work roman! Thankyou for sharing your diagnosis process. Very informative.