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KK Blackboard Yaw Gyro Not Working

dezertdog

Senior Member
#1
Hey guys,

Having an issue with a new KK blackboard (KK V1.6) where the yaw gyro doesn't seem to be working at all.

Lifts off very smooth and flies fine, BUT it’s quickly obvious I have no Yaw gryo. Controlling the tail servo via M4 I have authority over it (I can “make” it fly manually), but hands off results in a slow un-countered spin either direction at whatever rate it was going. Adjusting the Yaw POT from 20% to 80% seems to have no effect whatsoever. The roll and pitch gyros are working fine though. On the bench with the board armed and spun up at ¼ throttle, when moving the model in roll or pitch the gyros clearly compensate. When yawing, there is no tail servo compensation.

Digging into some threads I found the pinout for the yaw gyro daughterboard should be voltage (+5V)/signal (+1.5V)/ground. I’m getting continuity between voltage and +5 on the rail, and also ground continuity. With the model on a lazy susan and a multimeter on the pinouts, I read +2.11V, +.08V and ground while stationary. While yawing the model and reading the voltages, I’m seeing no change (the middle pin I believe should be fluctuating with signal voltage). I have taken a fine tip iron and resoldered the three connections, and get the same results.

I’m still searching/reading threads to see if I can come up with something. Some threads recommend reversing the Yaw gryo. That doesn’t seem to be the issue as I don't see the servo move at all and I can fly without erratic yaw movement and hold a heading manually with focus and light input. Also with my other tricopters I never had to reverse this gyro.

Any input would be appreciated!
 

dezertdog

Senior Member
#2
"Other things being equal, a simpler explanation is better than a more complex one."

Bad board. After an hour or so of messing with gains and reversing etc, I dropped a spare board in and what do you know, bad yaw gyro. Problem solved!

This thread is a good debug article for those having a similar issue though. I've read countless threads online where the Yaw daughter board had a bad solder joint and just needed to be redone etc.
 

colorex

Rotor Riot!
Mentor
#3
Bad board. After an hour or so of messing with gains and reversing etc, I dropped a spare board in and what do you know, bad yaw gyro. Problem solved!
I was going to guess that, but I decided not to fill up the page with guesswork. Glad you got it fixed!