I am trying to replace my mobula7hd flight controller. I bought a crazybee f4 version 3. I soldered the battery wires and the VTX to the fc. I decided to cross my fingers and plug in the battery prior to soldering the camera. It smoked and I quickly unplugged. I tried to open betaflight to see if it would still work, and betaflight launched and I got led lights on the fc. Is my fc fried or does it still work since I could access betaflight? (I know I need to use a smoke stopper, I just ordered the parts)

I then got out my multimeter and checked for continuity and there was no continuity between the ground and the positive wires. What would be the cause for the smoke, since I don’t have continuity between the two wires? My soldering is probably not the best and might end up on that thread about bad soldering, but are there things to lookout for? For instance, it appears a tiny bit of the copper on the board where the battery wire connects was not covered by solder. Would that cause smoke?

I’m very green at soldering and electronics, and am having a tough time picking it up. Any tips on the best way to go about learning would be very helpful....I’ve watched a ton of videos.

When you plug an unbound Crazybee F4 Pro V3 board into a USB cable, normal behaviour is a constant red LED (3.3V rail indicator) on the top of the board at the front along with a flashing green LED (status indicator) also on the top of the board in the middle, while on the bottom of the board you may get a flashing red LED near the front (unbound receiver status) if you have one of the FCs with a built in SPI receiver.

You should get the same with just a LiPo plugged in (no USB). If you don't see any LED activity with a LiPo plugged in then you will have likely fried the onvoard 5V regulator.

As for soldering, lots of practice on test boards. There are plenty of YouTube videos that show you the correct technique. Make sure you use decent quality tin/lead solder with a 60/40 or 63/37 ratio. Stay away from unleaded solder or any cheap Chinese rubbish. You will pay a good money for decent solder (Kester, MG Chemicals, Loctite, Multicore to name a few), but it will be worth it in the long run. Also, on tbese tiny boards make sure you use a fine tip on your iron.

Much appreciated. It’s fried. I will give it another go.