A/P disappeared

E

ermed5

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Dec 21, 2023
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Wondering if anyone has experienced this. My A/P on the HDX has disappeared. We previously replaced the dual electronic ignition system, and the plane was AOG for some months. After getting back in the air, I noticed no A/P settings at all.. not even on the menus. It appears the HDX is not recognizing both servos at all... submenus show A/P in grey. Emails back and forth with Dynon walked us thru it... but still cant find the A/P servos. Had a very skilled avionics tech help, and we found power to both servos intact. (BTW, tech support with them is outstanding.. emails answered very quickly). We focused on faulty servos (unlikely, but possible). Both servos removed, sent to Dynon, and both functioned ok. The last suggestion was to again pursue power/ground/network. We know we have power at the connections. My next task is to trace each servo's wiring path.
Anyone have suggestions or maybe has gone thru this? Thanks.
 
The servos communicate through the two datapairs to the HDX. If you have verified power is good, and the servos check out good, then your most likely culprit is a loose DB9 connection somewhere between the servos and the main network. Start chasing your wiring bundle from the servo locations all the way back to the panel or hub where it terminates.
 
I had a similar problem and found it to be an intermittent where the power wire connected to the circuit breaker. I had separate power wires to the roll and pitch servos, but they were both connected to the same circuit breaker. I had checked the power several times and it was always good. Worked with Dynon and they were puzzled, too, as of course one would be. Eventually, I found an open during a test. Fixed the connection and all is well. Just one experience.
 
Firstly, if you have had Dynon on the phone, did they ask you go to into the network config and discover all the devices? If you look at the status of them in the netork setup screens, they may give some indication (not there, or marked needing a software update)
Speaking of which, did you recently update software? Do this as if the servo software is out of sync with the HDX, this may cause incompatibility and the HDX will ignore them on the network.

Are there any warnings in the messages menu on the main Dynon HDX screen?

Once you validate that the software is updated for ALL your devices.... then I second what @airguy stated.
If you had everything apart, Dynon network config screens confirm the lack of seeing any servos, then most likely, you're missing a network cable connection or you have a hub looped back to itself. That begs the question, do your servos connect through a hub? If so, does the hub have a path back to the HDX? Is the network cable going through the Autopilot button panel? If so, does that also have a path back to the HDX?

For ghosts in the machine...Do you have a remote magnetometer added? Post my install, I had to add circle back and add the remote mag, and that thing, once added to the network kept causing AP disconnects. I had to lift the yellow wire from the DB-9 connection at the remote magnetometer. This issue likely isn't yours, but throwing that out there just in-case. Might be simple enough to unplug the remote magnetometer and rescan the network to see if they come back to life. Don't forget to redo all the things you just undid! :)

I know that's kind of a brain dump, but as a recent soup-to-nuts installer in my RV-10, a lot of this is still fresh in my mind.
I hope something here helps....
 
Mike, MANY thanks (and airguy and jnmeade). These suggestions are SO helpful.

Yes, I had many contacts with Dynon techs, and they are always receptive and provide outstanding customer care. I had both of my units sent back to them, and they functioned ok. I just reinstalled them 2 days ago, and pout... its like they're not even there. When I do the config, only 9 devices show up, and both servos are not seen at all (and AP is in gray). I checked the DB9's, and they look good. Prior to returning them, they did have power. I am currently doing what jnmeade suggested, which is trying to get behind the CB panel and move both AP power wires to a different breaker, to see if that gives the servos some life. Sadly, I need the fingers of an infant to get back there.... you can only pull so much on a CB panel before other connections say that's enuf.

This all started some months ago... not sure what did it. I had to change out my FlyEFII dual ignition system, as the previous legacy units were tired and likely caused a power loss at altitude.... talk about excitement. Plane was AOG for a few months awaiting the new ignition system. With the spaghetti wiring so tightly bundled behind the panel, it IS possible that something got dislodged (or worse yet, inadvertently cut) during install of the EFII.... its amazing how much unused wiring and zip ties you find just hangin around.

Yes.... everything goes thru the hub on the inside firewall. I checked all of those connections, and they are tight.

Software updates done each time Dynon comes out with one... data-wise... religiously. I have not done any other software or hardware updates, to the best of my memory. Servo software out of sync with the HDX/HDX ignoring servo software?.... hmmmm.... interesting. Would that mean all software needs to be reloaded?

I have no msgs on the main screen... its just that no AP selections are available at all. There's not even an AP selection available (next to TMR). Nothing on the 'top bar' of any screen page, either.

The hub/loops/path back... none of that wiring has been changed at all since purchase (even when AP was functioning).

Yes, I have a magnetometer. I will try to unattach and reattach, and see if that changes anything.

Brain dump? Hardly! I cant thank y'all enough. Back to the hangar now.
 
Do you have the ability to pin a cable? You could make a long DB-9 network cable and connect the servo direct to the new cable and plug in direct to the HDX. You still have to pull the black and red wires from the cable and route to power/ground. That gets a little complicated, but not terribly so. You really ONLY need the 2 twisted pairs and then power/ground to test out.
Where are you geographically? If you're in the northeast I'd be happy to help in-person.

Mike
 
Mike, MANY thanks for the offer. Sadly, I am in the cornfields of Nebraska... a little ways from NH! And out here, few techs/shops will work on experimentals, even tho much is standard in my Glastar.

More to come. Isaac.
 
ermed5 said:
Mike, MANY thanks for the offer. Sadly, I am in the cornfields of Nebraska... a little ways from NH! And out here, few techs/shops will work on experimentals, even tho much is standard in my Glastar.

More to come. Isaac.
Click to expand...
I just noticed this, checking all connections on back of the AP head. When the DB9 is removed, it flashes red slowly. When I reinstall the DB9, the LED flashes red rapidly. The AP head is lit… so there’s likely power to it. But what does the red slow/ quick flash mean.
 
By AP head, do you mean the HDX? ...and specifically, the ethernet port. Per the install guide...
Observe the lights on the Ethernet port. Unlike other Ethernet ports, these lights are used
for display status:
o Yellow light on: Power on pins 1/20 (power/ground).
o Yellow light off: Display not receiving power.
o Green light flashing: Normal when display is turned on, or turned off with a SV-BAT-
320 connected.
o Green light solid on or off: Something is wrong with the SkyView display. Contact
Dynon Avionics Technical Support ...

if you're referring to the ADSB-470 (per the install guide)
o Flashing Fast: The SV-ADSB-470 is operating normally, is configured and
communicating with SkyView over a correctly-configured serial port, and is receiving
GPS data from SkyView.
o Flashing Slowly: The SV-ADSB-470 is rece

Other modules:
modules such as the SV-ADAHRS-200/201, the SV-EMS-220/221, and SV-ARINC-429,
observe the red LED light near the SkyView Network connector:
o Flashing Fast: The module is operating normally and is configured and
communicating on a SkyView Network.
o Flashing Slowly: The module is operating normally, but is not active on SkyView
Network.
o Off: The module is not receiving power (from a SkyView Network / Display)
o On Solid - the module is receiving power, but is not operating normally.

I hope this helps.
 
I should have been more clear. This was the back of the AP control panel (SV-AP-PANEL/H).

Looking at the above (if the control panel functions the same), then a fast flash means the module is operating normally?

I've been checking all connections, and still find no AP at all. Servos still not found.
 
Since the Skyview does not need the SV-AP-PANEL to detect servos, it's doubtful that's the problem. You could always just disconnect the SV-AP-PANEL. The Skyview system does not need it to operate autopilot servos. That would at least eliminate the SV-AP-PANEL as a cause of the malfunction.
 
Just double checking here - you know you have good power AND ground to the servos? If you lost a ground connection it would act just like a lost power connection, even though you would still show 12 volts on a meter at the servo and assume you have good power.

Ask me how I know...
 
I will check that again.

But, let me ask one more question.... and I dont know why it didnt click on me earlier. The top bar across both of my HDX screens contains no info other than the UTC clock. No frequencies, no txpdr... nothing. Just the clock. ???
 
If you have power to the comm and transponder, they should show up there. If all those things are good then you've either got a bad harness connection somewhere, or you've lost a main feed to the HDX from a hub. Run your configuration routine again and see if you can "see" the comm or transponder. If those are missing also, that's a big clue.
 
This is based on memory, as I ran config again today, after removing both servo grounds and the AP disconnect, putting on new ring terminals, and attaching them to different ground connections.... but no change. I (continue to) have only 9 devices found... all Dynon units.. ADHARS, etc. My #1 com is an Avidyne IFD (nav/com/GPS), and com 2 is a separate Garmin unit. The txpdr is an Avidyne unit. So, those three are not 'seen' (or at least they haven't been seen) since this all started during the any of the config runs. Were they seen prior to these events? Dont know, as I never had to run configuration prior to this mystery.

Gonna take a closer look at the hub.
 
ermed5 said:
This is based on memory, as I ran config again today, after removing both servo grounds and the AP disconnect, putting on new ring terminals, and attaching them to different ground connections.... but no change. I (continue to) have only 9 devices found... all Dynon units.. ADHARS, etc. My #1 com is an Avidyne IFD (nav/com/GPS), and com 2 is a separate Garmin unit. The txpdr is an Avidyne unit. So, those three are not 'seen' (or at least they haven't been seen) since this all started during the any of the config runs. Were they seen prior to these events? Dont know, as I never had to run configuration prior to this mystery.

Gonna take a closer look at the hub.
Click to expand...
Ahh - ok, the external comm and transponder won't show up on the top bar of the Dynon, that is just for Skyview devices. No help there, I'm afraid.
 
If the servos are grayed out in the configuration you will need the Dynon tech on the phone. Just went through this on a brand new install. Fixed the problem in about ten minutes of furious button pushing. Good luck.
 
ermed5 said:
This is based on memory, as I ran config again today, after removing both servo grounds and the AP disconnect, putting on new ring terminals, and attaching them to different ground connections.... but no change. I (continue to) have only 9 devices found... all Dynon units.. ADHARS, etc. My #1 com is an Avidyne IFD (nav/com/GPS), and com 2 is a separate Garmin unit. The txpdr is an Avidyne unit. So, those three are not 'seen' (or at least they haven't been seen) since this all started during the any of the config runs. Were they seen prior to these events? Dont know, as I never had to run configuration prior to this mystery.

Gonna take a closer look at the hub.
Click to expand...
Your coms, and xponder are not Dynon network devices. They are serial devices and won't be detected in the network config page. Only things that are Dynon brand, and connected to the Dynon 9 pin connection are devices that are detectable. I still think you have a leg of your network that's just not connected.
 
What an adventure. Finally got it fixed. (and BTW, Don at Dynon, et al, were VERY helpful and walked me thru things). Suggested I try alligator clip direct from battery to servos, and they both worked. But when hooking things back up, nothing. Then alligator'd from battery to both servo power ring terminals by the C/B. It worked. Thinking possibly a bad C/B, got a new one yesterday from ACS. But that didnt fix it either. So, put on new ring terminals and attached both to a different C/B, and voila. Flew today and things back to normal. Maybe something localized at the bus bar? It's the devil to get clumsy fingers in there AND manage those tiny screws!

Thanks, everyone, for the helpful suggestions and comments. I was losing sleep over having to remove the interior/pull up floorboards to follow bundles. But it all worked out. And learned a lot, too.
 
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