Tricopter tail servo problem

Fyathyrio

Member
I recently finished my 1st tricopter and only my second multirotor build. This time I used Cleanflight and an Armattan Mullet (Naze acro clone). Everything seems to work great, except for some unknown reason my tail servo won't move. I've run out of ideas, and my google-fu has failed me. Any help is appreciated!

Details...
* The digital tail servo works perfect when attached to my servo tester
* Tail servo plug has power & ground correct, and I have continuity from plug to signal pin on flight controller.
* Servo plug is aligned properly for power, ground, and signal.
* Servo option checked in Cleanflight config tab, servo connected to pin 1, motors (pins 3-5) respond correctly to throttle and tilting of the craft by hand.
* Everything responds correctly to Tx inputs as observed in Cleanflight
* Pins are soldered cleanly, no bridges.
* Servo powered by it's own Pololu to help avoid brownouts, but there is continuity between ground on servo and ground on FC.
* Using Emax 2204 motors, and Spider 12A opto ESCs flashed with BLHeli 14, Oneshot enabled, active braking enabled.
* Using Lemon DSMX Spek sat clone serial connected Rx. Initial sat Rx binding with Tx done with Lemon DSMX stabilized Rx.
* Tx and FC channels configured correctly as TAER1234.

Odd things noticed...
* When I check the motors tab in Cleanflight, the Aux 3 tab (on the right of screen) moves with my rudder throws on my Tx.
* The servo "ticks" and moves so slowly when sitting powered that you won't notice movement unless looking away for a bit.

Questions...
* Is there a way to reconfigure the FC to try tail servo via FC pins 2 instead of 1?
* Could this be settings under the "servo" tabs in Cleanflight?
* Any other things I've not thought of?

Thanks,
Mark
 

NHS77

Senior Member
I'm just building my first Tri right now so I don't have the expertise there. However: If you got a board capable of running clean flight why not give David Windestals custom tri firmware a try? downloadable from rcexplorer.se or check out his naze setup tutorial video.... Perhaps this fixes things.

https://youtu.be/xY1EJpPZgSc
 

Craftydan

Hostage Taker of Quads
Staff member
Moderator
Mentor
Looks like most everything looks right on your setup.

The Aux3 issue does indeed seem Odd, but because the connection is via Sat, that's got to be something buried in your radio -- a Mix perhaps? Either way, so long as Aux 3 isn't assigned to any modes on the board it shouldn't affect anything.

As far as the Servo, So long as the Servo's UBEC is truly outputting 5v, the only reasons left it wouldn't respond sensibly would be in the signal (FC not generating the right signal, or the signal isn't making it there), or in the servo (broken). The latter is easy to test -- plug it into a servo tester or RX and see if it behaves.

As for the former, yes it can be reassigned to position 2 through the custom servo mixing in CLI . . . but 1.9 has had some reports of having issues in the servo code. I'd recommend re-flashing to the latest 1.8 and seeing if that resolves your issues.
 

Fyathyrio

Member
Thanks for the suggestions, I finally figured it out. The HK specs for the servo said 4.5 - 6v, so I used a 6v Pololu I had laying around to run the servo. For some reason the servo would not react to FC input when powered by 6v, yet was fine using my 5v powered tester. Once I swapped a 5v Pololu in, it's acting fine. Now it's time to tweak and tune PIDs.