Dynon SV Random AP disconnects RV10

[Janekom]

I am trying to figure out how to solve this problem. Not my RV10 but I would like to solve the problem for him. Is seems that the AP will disconnect randomly on most flights. Sometimes without warning and sometimes after a few slip warnings. He has a SV42 as roll servo and a SV42 with torque enhancer arm as pitch servo.

I cannot find any physical installation problems at the servos. We have searched this forum for "standard" setup parameters and have set the AP up that way.

So where do I start? I suspect wiring issues. Can someone in the know tell me what the most probable cause for this is and where to start looking?

Settings from memory:
Roll
Torque 70%
Sensitivity 10.0
Roll Gain 0.4 Def is 0.0
Bank Angle Limit 30 degrees

Pitch
Torque 70%
Sensitivity 10.0
Pitch Gain 2.0
Altitude Gain 0.6
Pull Rate 1.0
VSI Gain 0.6
G Error Gain 1.0
G Error Limit 0.25
Def Climb Vert Spd 500 FPM
Def Descent Vertical Spd 500 FPM
Max Airspeed 180 Kt
Min Airspeed 90 Kts

 

[jakej]

An easy check, simple least amount of work first, would be to -
1. disconnect the disconnect wire at the roll servo - if that doesn't work then -
2. also do the same with the Pitch servo leaving the roll disconnected
3. Let us know if the above doesn't 'fix' the issue

 

[Dynon]

A couple of questions:

Is he using expert mode or simplified mode?
If expert, is the flight director still active (IE, the AP bar in the top left is still populated with modes/numbers, but the AP isn't connected) when the AP disconnects?
And does he have the SV-AP-PANEL?
Assuming audio is hooked up, are there any error messages that happen concurrently on the message button or aurally other than "Autopilot Disconnect"?


I'd be looking at the disconnect wires that each servo has. If one was getting accidentally grounded out, that would disconnect the Autopilot. Other than that, only the on-screen controls or the SV-AP-PANEL controls will disconnect the autopilot. Even when the AP slips, the AP won't disconnect until you do it manually.

 

[Janekom]

Thank you very much for your reply.
He is using simplified mode and does not have the AP-PANEL. He did confirm that the audio is hooked up and can hear the AP disconnect message.

Zooming in on the wiring for now

 

[RJ]

I had the exact same problem in Expert mode
The fix for my Aircraft was very easy =
Loose thumb screw connections at the rear of the 4 "extra add on" Button / Dial up panels & radio.(Check both ends of wiring)

I have the D1000 plus the 4 extra panels fitted to my Aircraft that are available as add on extras.
I'd say engine vibration caused my problem shortly after my Aircraft was delivered.
Everyone was thinking / looking to deep for my problem.
I eventually solved the problem myself after many emails & phone calls over at least 10 months.
I hope this info helps
Rule 1... Start at the connections
Cheers
Hawke