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HELP: Gremlin FC issues

#1
So i recently bought and built my gremlin, but haven't flown it until now because of the cold. Upon first flight, after giving it the smallest amount of throttle, the quad sporadically twitched and yawed. So, i went back and hooked it up to betaflight, took off the props, and went to the receiver section. Double checked that all inputs looked good there. Then i went to motors, where i double checked the direction of each, all good. I then tried to recreate the incident, so turned on my Tx and gave it a bit of throttle. Instead of seeing all 4 motors go up, there was complete chaos. While that was happening i checked my Tx again just in case, and all good. This seems like a FC issue to me, since the motors were reacting fine one at a time through betaflight. Any one else have any other ideas? Think they will replace my FC?
 

PsyBorg

Wake up! Time to fly!
#2
Welcome to Flite Test mate.

Two things are going on that are more then likely two separate things. First is the craziness on the bench. This is normal behavior. The FC is trying to make the quad be level. It will change what ever motor that will help get it to where it wants to be. When that correction does not fix the issue it tries again and a again and will never get the quad level. Pick the quad up and watch everything snap back into center and start trying again to get to level.

Now to the yaw twitching. VERY common with these small quads and the Femto FC. There could be several things that can cause this. Most times it is something barely bouncing on the frame like the camera antenna, esc wires, antenna wires, pretty much anything that "Flicks" the frame will cause that yaw twitch each time if happens. It could also be the way you have the FC mounted is to stiff. Finally I had my Alien do this on its maiden.. The JR connector from the receiver was not allowing the pins to insert far enough for perfect contact and the signal wire was having intermittent breaks. Ever since they I hard wire all my receivers. Its 3 solder connections and well worth not having that issue ever again.

Look your quad over carefully for anything loose that could be tapping the frame, check all your connections and solder points and see where that gets you. If you still have issues get us a short video, some detailed pictures of your connections and some screen shots of your settings and we can figure things out from there.

Good luck I hope its something simple for you.
 
#3
I've configured a whoop before and the leveling of that board was much more tame than what is happening here. I can't post a video currently, but the motors are going anywhere from 1100-1800 in betaflight, within milliseconds. I have a feeling this is causing the yaw as well, but i'll definitely go back and check my connections and soldering. Thanks for the advice