A/P Servo Err on startup

[swatson999]

This has happened to me a time or two before...

On power-up of the SV system (actually, the whole airplane, via the Master...I have no separate Avionics Master), which includes all the subsystems (A/P Servos, ADS-B, XPDR), I get either a "Pitch Servo Err", a "Roll Servo Err", or both at the top of the screen, and a Warning message about the servo(s) being off-line.

No amount of futzing with the system will recover them, but a complete power-down (master and alternator off) and power back up and they're all good.

Happened again today, on the second start-up (power up, no problem, engine start, taxi for fuel, shut down; power up...both servos off-line...engine start, power cycle, all good).

I grabbed a diagnostic file and will upload it.

I suspect this is another timing issue...either the servos are being pinged as part of an aliveness check before they're fully ready to respond, or the comm link is out of sync (or something else similar).

 

[jakej]

Steve
I think you are correct.

We had issues here with a SV TXPDR ocassionally transmitting incorrect (although the correct one was entered) Hex codes, the fix was to boot up the SV's first & then the Transponder. Seems like you're having the same sort of problem.

For others reading this I'd suggest that it would be a good idea to power up any other "peripheral' equipment, eg autopilot & Transponder, after the SV boot as mentioned above

Jake J

 

[dynonsupport]

Steve,
While we don't have perfect information why this happens, it's happened in my airplane two or three times (over 700 hours) as well. It appears it's the servos being annoyed (for lack of a better term) by the engine start. I've seen them be there before start and then gone after. If I pull the breaker for one servo and power cycle just it, it comes right back. Nothing else I have been able to do but a power cycle fixes it.

We've been unable to reproduce it in the lab, which makes it very hard to do anything about. We've never once heard about it happening once the engine was running.

As far as we can tell, it's not a timing issue in any way. The SkyView Network is completely designed to have anything come on and off at any time. It very much appears that the servo itself has decided to stop talking on the network because of some anomaly that happens once in a blue moon during engine start.

Jake,
As an FYI, the issue with the transponder has been resolved in the 2.6 firmware.

 

[swatson999]

Steve,
While we don't have perfect information why this happens, it's happened in my airplane two or three times (over 700 hours) as well. It appears it's the servos being annoyed (for lack of a better term) by the engine start. I've seen them be there before start and then gone after. If I pull the breaker for one servo and power cycle just it, it comes right back. Nothing else I have been able to do but a power cycle fixes it.

We've been unable to reproduce it in the lab, which makes it very hard to do anything about. We've never once heard about it happening once the engine was running.

As far as we can tell, it's not a timing issue in any way. The SkyView Network is completely designed to have anything come on and off at any time. It very much appears that the servo itself has decided to stop talking on the network because of some anomaly that happens once in a blue moon during engine start.

Jake,
As an FYI, the issue with the transponder has been resolved in the 2.6 firmware.

Yeah, I agree...it's very, very rare, so not that much of a concer, and a power cycle fixes it. IIRC, though, this last time I got the error *prior* to engine start (I'll have to check the logs to see for certain).

Anyway, I uploaded the diagnostic file, so just another data point you have available if someone wants to chase it down...

Thanks!

Steve

 

[jakej]

DS - Thanks for the 'heads up' on that with vers 2.6 as I wasn't aware :-[

Jake J