Spinning me rite round baby

[amxen]

ok so the thing is my tricopter was set up just fine and been flying just fine. So last night grabbed a plane or 2 n my try headed of to the field.

thought id give the tri a go first. lifted off ok but then it started to yaw clockwise. i thought it was the wind and added some input to counter it but it got worse. then it just spins around and i land. checked it over and it seems fine so i try again with a new battery and it did the same thing.

the servo see to move ok but it almost like some one else has taken control of the yaw  and started spinning it clockwise after about 20 seconded of flight.

what do you think? is the servo goosed ? or is the board

tricopter
kk2
simonk
hitec mg servo

[NickC]

had same thing on multii 2.1 and 2.2 on Crius but could weirdly get it to stop rotating after using my txr switches to change modes and then go back to level.   That said, later in the same day I was dialling in pos hold and rth PIDs which meant flying high as it would oscillate over about 6-10m and as I flicked out of one mode to level it started fast rotation and flew off out of sight.  Still can';t find it and that was 3 days ago.

Kinda thinking the servo and yaw mount parted company but that doesn';t explain why it set off at fair speed through some trees and into the land of lost tri-copters rather than staying relatively in place and spinning madly.

Did you ever get sorted?

[amxen]

yes it turned out to be striped gears inside the servo and it was ok to start with then the servo moved more hit the striped but then off it would go. new servo sorted it till i crashed doing stupid stuff

[NickC]

Amxen thanks for posting back and good call, the servo on mine was recycled from an old model in desperation (thanks to an amazon.co.uk sale of a servo turned out to be from China grrrrr so angry it wasn';t made clear before I committed) so its possible that although I thought I';d checked it out it had a stripped section maybe at a slight extremity of yaw. 

Still haven';t found it despite Loc8tor beacon onboard. very frustrating.

all the best

Nick