KK 2.0 Tricopter Yaw Servo Stopped Working

[jamieFL]

I built a Tricopter for a friend of mine. It was flying perfect. A few weeks ago he had a crash that broke a wood boom. Things got busy and I just got around to it.

Everything is fine, but the yaw servo just won't work. The FC is getting the proper signal from the receiver. The yaw servo is getting 5 volts on the red wire and the servo is energized when the FC is armed. I plugged a brand new servo directly into the FC and it was no different.

When I arm the FC and spin up the props, all motors behave correctly. The servo just won't move.

 

[jamieFL]

Is there a setting that I have misconfigured, or did the board somehow become damaged? I just did a factory reset and still no luck.

 

[califrag]

I had this problem before and it was due to a finicky servo extension (to yaw servo). Not sure if you are using one or not but maybe try a different one.

Do you have all three wires from the ESC servo leads going into M1/M2/M3 or are you only using the power from ESC #1 BEC to M1, and M2-M3 have only the signal wire from ESC? My yaw servo didn't like having M3 without the additional power leads from the ESC connected.

Just for the sake of eliminating the servos as an issue, you have hooked them up directly to the receiver and tested them without going through the flight controller, correct ?

You can check to make sure the M4 output on the board isn't messed up by changing the motor layout to a quadcopter, then change one of the motor/esc from M2/M3 over to M4 and spin it up (without props and very low throttle). If the motor doesn't work then it could very likely be the board.

Do you have the board mounted on nylon standoffs ? or is it attached directly with tape or something else? Make sure it isn't touching any of the screw heads and shorting something out on the underside of the board.

Also double check the transmitter settings and make sure rudder is still assigned on the proper channel with the proper weighting, and check the dual rates and expo settings if applicable.

Let us know if you have any luck or what the results of the tests yields.

 

[jamieFL]

Thank you. I've tried everything I know how.

My first thought was a bad servo. My second was bad servo extension. I plugged a brand new servo directly into m4 with no luck. I've not tested the servo it's else to the receiver.

I have the board velcroed to the inside of the foam box it came in.

I will test the servo after I try your last suggestion of switching setup to quad. That is a good idea.

 

[jamieFL]

califrag,

Thanks for your advice. I did exactly what you said and found out that the KK is working fine. I realize now that when I plugged a new servo directly into the KK m4, it was getting no power since I was supplying no power through m2-m8. I believe that the signal wire in the servo extension was bad as I had previously tested the +5 and ground wires. I don't know if this makes any sense, but I got it working.

 

[califrag]

Awesome glad you got it working, I was looking forward to an update.

So yeah looks like the yaw servo requires BEC power on M3 in order to work properly. I ran into the same problem when I tried to run only the signal wire from the ESCs to M2 and M3