Hey all,
My school team is building a drone for a golf ball drop competition. We built the drone and got the claw connected and working after figuring out how to set it up on Betaflight. We connected the FC to the battery and Betaflight for testing. The claw worked for a couple of opening and closes, but then froze. A couple seconds thereafter our FC started smoking. We immediately unplugged everything and let it cool off. We attempted to pull the SD card for logging but the card seems to have been fried and won’t be detected at all.
On the next time we attempted to start up the drone through battery, the power light was barely flickering on on the FC and the activity light wasn’t on at all, but the ESC gave the three start up tones. The FC powers up normally and responds when connected to the computer, but still won’t provide receiver input when the battery is also connected at the same time. The pictures attached show the wiring of everything and any help in identifying if we need anything else to run the servo for the claw.

Parts:
- Kakute H7 v1.3
- TEKKO32 4-in-1 ESC
-DJI O3 VTX and receiver
- claw voltage range is 4.8-7.2v

The claw is running directly off the 5v, gnd, and LED_STRIP pads with all remapping done and set up for that. The m4 pad was already bad before this build, so motors are remapped for m5-8.

I’m not seeing any pictures, but those would definitely help.

If it smoked, you know something is likely fried.

If you’re only hearing the first three esc tones but not the additional two tones when plugging in your battery, and can still connect to betaflight via usb- you either fried the 5v regulator or have a short somewhere on the 5v rail. Check with a multimeter to see if you have a short between a 5v pad and ground. If not, check to see if you’re getting 5v on a 5v pad with a battery plugged in. Depending on how much amperage that claw pulls, it may have been what killed the 5v regulator.

If it’s just the 5v regulator, you can wire in an external 5v bec to power the flight controller, as well as the claw (depending on amp draw of the claw, it may need its own bec).

It sounds like you are using a dji controller through the o3 unit. If betaflight is no longer registering receiver input, double check your wiring to the o3 unit- make sure nothing got disconnected or burnt. Are you getting 9v on the 9v pin/pad with a battery plugged in? If yes, can you see video through goggles?

For your "claw" is that a servo mechanism? It would be best to double-check the power draw of the servo, as the 5v rail on the FC could be insufficient. The FC you mention is rated for max 2 amps continuous on the 5v rail, and this power is shared for all components on/connected to the FC running 5v/3.3v. If it is a tiny 9g servo, I believe the stalled current draw is close to 1 amp, but if it is a larger or multiple servos then you would not want to power it directly off the FC, you would need to add an external BEC.