YAW Servo delay / glitch


I am new to APM, but have used Multiwii for a while.
I use to find out alone but in this case, I can’t find out :

My YAW servo is running perfectly fine while connected directly to the RX.
When I connect it to the board (APM 2.5 running 3.1.2 Tricopter firmware), it becomes delayed.
Any stick input is making the servo move 3 / 5 seconds later.
It’s the same when I rotate the copter, the yaw compensate with a big delay.

I power the board via a 3A UBEC connected to the OUPUT CH8.
JP1 is ON.
ESCs Calibrated.
MAG and ACC are calibrated.
RC is calibrated.

Everything seems to be fine, the APM Planner’s HUD seems OK, it updates well when I move the copter.
I can see horizon and compass move as I move the copter.

Do you have an idea ? I am nearly giving up and waiting for my Quad parts arrive…
I can’t find out and it’s driving me nuts.

Thanks for reading me.


weird problem, many views but no ideas.
I hope this is not a faulty board…

And still didn’t receive all the parts for a Quad. Have to switch back to multiwii… :neutral_face: :question:

Can you show a log? It’s normal for there to be a very small lag, but not 3-5 seconds like you suggest. If there is, something must be wrong with your parameters, or the hardware.


how can I show you a log ?

I’ve done an Erase via the CLI, and now servo does not move anymore.
The APM is reacting like a QUAD, when I push Yaw stick, the left/right motors change their speed…

It’s absolutely insane…

Here is a video to illustrate the delay.
It’s not 5s this time, but it’s already too much.
Moreover, it’s for from smooth moves.