Pitch servo went intermittent again

[lancair360]

History - pitch servo went intermittent last winter, would drop offline and maybe come back cycling the power, maybe not. Once offline if you did a detect network it wouldn’t show up. Pitch servo was overhauled by Dynon last winter.

It’s worked flawlessly since including a trip from Seattle to Texas. On the return now and on initially power up the pitch servo would drop offline after a minute, maybe more. Power cycle brings it back. Once offline a detect network failed to find it.

Landed for fuel, powered up and did network detect and it showed up, then promptly dropped offline.

Flying I was able to get it online and couple the autopilot and it would last for 3 minutes to near an hour before dropping off line. Power cycle always brought it back. Worked normal when coupled and up and running.

Will contact Dynon support soon. Any thoughts anyone? It’s a recent overhaul servo too. Rides were smooth, no turbulence. No regularity to the failure.

 

[Raymo]

Consider swapping it with the roll servo and see if the problem moves with the servo. Alternatively, make a harness that will allow you to plug the pitch servo into the roll harness and vise-versa for additional ground testing.

 

[lancair360]

Consider swapping it with the roll servo and see if the problem moves with the servo. Alternatively, make a harness that will allow you to plug the pitch servo into the roll harness and vise-versa for additional ground testing.

Good idea, thanks. See if i can whip something up.

 

[lancair360]

Just for info for everyone...

Working with David at Dynon. Sent diagnostic files to see if there is anything in there. So far I've been running for 2 hours with no failure. Also, upon his request, I ran several differnt squawk codes through the transponder to look for RF interference. So far, no luck, unfortunately it works fine! haha!

At this point since i can't get it to fail there is no reason to swap harness with the roll servo, but that's still on the table.

 

[lancair360]

Ran the aircraft last night for an hour, tested both comms for RF interference with the servo without luck. It did fail twice but could not be related to anything I did.

Did find a loose wire but pulling it only gave an amber data error, not a servo offline message. Fixed that wire, unclear if it's related to the servo dropping offline or not. Dynon is still looking at diagnostics and talking with the software folks. At this point it doesn't make sense to swap servos or wiring between pitch and roll as we cannot get it fail.

Will fly some and see what I can learn. So far a power cycle of the autopilot brings it back every time.

 

[lancair360]

About 3 more flight hours and a couple hours in the hangar powered up and no failure of the pitch servo. Yay?