New gremlin and I'm stumped! No trim??

lancair360

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Oct 19, 2020
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Another nugget of info and a reminder as to why this is a huge deal. When I get the AP panel offline master caution I lose my trim. That’s not suppose to be possible. As long as you got power and ground running through the panel trim is fail safe. Well it’s not.

Now if I have everything up and running and I pull a network cable out of the AP panel and get a master caution AP panel off line my trim still works! But if it fails in its normal failure mode I lose all my trim.

It’s not a 12v problem or it would surface before the second screen boots. It’s something in the computer and/or network. At this point it seems Dynon is stumped and out of ideas. The current plan is to remove the AP panel from the loop and fly normally, see if any other failures occur they may be being caused by that screen.

Another nugget of info. I swapped the screen left to right right to left and the problem stayed on the right side of the plane and didn’t follow the screen.

The only thing I haven’t done is swap the cables on the two D9 ports on the back of the AP panel but I suspect only one side will trigger the AP panel offline and not the other, and it’ll stay that way. I don’t know if that means the failure is in the new AP panel or if it’s just an artifact of the serial network but everyone is out of ideas.
 

Rhino

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Go ahead and swap the cables.

Do you have the SV-AP-TRIMAMP?
 

CanardMulti

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Another nugget of info and a reminder as to why this is a huge deal. When I get the AP panel offline master caution I lose my trim. That’s not suppose to be possible. As long as you got power and ground running through the panel trim is fail safe. Well it’s not.

Now if I have everything up and running and I pull a network cable out of the AP panel and get a master caution AP panel off line my trim still works! But if it fails in its normal failure mode I lose all my trim.

It’s not a 12v problem or it would surface before the second screen boots. It’s something in the computer and/or network. At this point it seems Dynon is stumped and out of ideas. The current plan is to remove the AP panel from the loop and fly normally, see if any other failures occur they may be being caused by that screen.

Another nugget of info. I swapped the screen left to right right to left and the problem stayed on the right side of the plane and didn’t follow the screen.

The only thing I haven’t done is swap the cables on the two D9 ports on the back of the AP panel but I suspect only one side will trigger the AP panel offline and not the other, and it’ll stay that way. I don’t know if that means the failure is in the new AP panel or if it’s just an artifact of the serial network but everyone is out of ideas.
I can really feel your frustration. Since the problem as manifested stays w/ the right side regardless of which screen resides there, it screams to me that there is some sort of flaw with the wiring on the right side. Chasing down a wiring harness problem has to be the very least favorite task of any experienced aviation electronics tech I've ever talked to. Especially if it's only intermittent.

Ken
 

Rhino

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....Chasing down a wiring harness problem has to be the very least favorite task of any experienced aviation electronics tech I've ever talked to. Especially if it's only intermittent.
I could tell stories, but they mainly bring back painful memories.
 

lancair360

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Oct 19, 2020
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215
New network cables going in Friday when I get back from this trip. Will swap D9 left to right before that and see if behavior changes. Then new cables go in. Its behavior is a computer or network issue for sure. Whether that’s boot code or bit flip or cable who knows.

No trimamp installed. Not required, trim electrics draw isn’t that high.

since I know it’s a network issue it’s on one of the D9 cables, and those come pre wired from Dynon so I don’t have to ring them out, just swap. The D15 cable is intact because that’s just power and ground and all the trim circuits to both sticks and I can easily verify that all works.

the fact that swapping out the (broke) AP panel two years ago fixed it and now I have a new AP panel and it’s intermittent is rough.
thank you all, keep you posted.
 

jessesaint

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Nov 15, 2006
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You lose all of those things when you unplug most likely because the second port on the 2nd screen is probably connected to a hub or something that connects the AP servos, ADAHRS and ARINC. Go on Amazon and buy a male-male 9-pin gender changer and remove the problem screen and tie to two network cables to each other through the gender changer and see if the problem goes away. If so, then the 2nd screen may have a problem in it that is killing something on the network.
Also, if the Skyview was a retrofit, then it is possible that the trims aren't going through the AP Panel. If you have a 3rd connector on the AP Panel (the 15-pin connector), then the trims are likely going through it. If not, then they are not. Losing the AP Panel on the network will not cause the trims to not work, I don't think. They relays should still work fine, if I am remembering correctly.
 

lancair360

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Trims go through the AP panel. And that’s the frustrating part. Shouldn’t lose trim when you lose the AP panel but I do. It’s a failure not possible and Dynon at this point is stumped. I swapped screens left to right and the problem doesn’t follow the screen. Though it is intermittent and can’t fail on command so it’s even harder to find.
 

swatson999

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So this may be more difficult to do, but if you have a friend or friends with Dynon systems, you could start to eliminate *those* elements by temporarily swapping them with your friends', one item at a time, to see if the problem goes away or remains. If it sticks around, then it wasn't that component (EFIS, AP panel, etc.).

Time-consuming and a PITA, but it's one more tool in the debugging bag to think about.
 

lancair360

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So this may be more difficult to do, but if you have a friend or friends with Dynon systems, you could start to eliminate *those* elements by temporarily swapping them with your friends', one item at a time, to see if the problem goes away or remains. If it sticks around, then it wasn't that component (EFIS, AP panel, etc.).

Time-consuming and a PITA, but it's one more tool in the debugging bag to think about.
Since we know it’s a network issue that’s leaves us with the AP panel itself, the two screens and the cables. And since the failure is only happening after the right screen boots that narrows it to one screen, one cable, and the AP panel.

Given it’s a failure mode that’s not possible should narrow it further but the fact Dynon is stumped means I’m on my own. And it’s intermittent which makes testing difficult at best. It ran flawlessly for two years since AP panel replaced in 2021.

ground power, Wi-Fi camera in the cockpit and 24/7 avionics run time on the schedule for this weekend.
 

lancair360

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Back from work. Two new network cables installed to the back of the AP panel. One goes to the hub and the other to the right hand screen.

Got the failure 7 minutes after power up. Then 3, then 2, then as soon as the right hand screen booted. Repeat as much as you wanted. After a few minutes powered down failure occurs after a few minutes, then quicker and quicker.

I swapped the screens left to right and the failure followed the screen. Dynon agrees it’s the screen or something with how the network is loading. They are meeting Monday about it. The whole building knows about it since the failure mode technically isn’t possible.

But this is a result! I’m happy we learned something.
 

lancair360

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Spoke with Dynon yesterday. No one can figure out how I’m getting a failure that’s not possible yet. They aren’t very suspect of the new AP panel. Waiting to see how we will move forward. Hopefully hear more later today or tomorrow. I’m grounded until it’s fixed. No trims means no fly.
 

Marc_J._Zeitlin

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Spoke with Dynon yesterday. No one can figure out how I’m getting a failure that’s not possible yet. They aren’t very suspect of the new AP panel. Waiting to see how we will move forward. Hopefully hear more later today or tomorrow. I’m grounded until it’s fixed. No trims means no fly.
If I understand the failure modes correctly, if you bypass the AP panel, the trim still works manually. Why not just jumper the Skyview network cables around the AP panel, taking it completely out of the network, and just manually trim? Then you can at least use the plane while they figure out the rip you've caused in the space-time continuum.
 

lancair360

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Totally can if I wanna go flying or need to take the airplane somewhere. Sounds like they are building a screen for me to swap in right now. We’re thinking a component inside one of the screens is bad. So I’m in the middle of differential diagnosis right now. Don’t wanna put it all together just to take it apart again in a day or two to swap parts around.

So I just fly my other plane! Can’t wait to get Dingo back up and running though.
 

lancair360

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Still waiting to hear from Dynon. They are going back over diagnostic logs now that they can narrow the search.

I did a network configure after the AP panel offline master caution to remove the panel from the network. Funny thing…even after doing that the trims still fail after the slave screen boots.

Airplane has been squawked near 6 weeks now and solidly ground for 4 except for a couple flight tests.
 

lancair360

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Spoke with Dynon on the phone today and a dozen more emails. The AP panel has two D9 connectors and a D15 which holds trim power and ground and all trim switch wires. The software guys saw several repeated instances of runaway trim. Though my trims never moved and I never got s trim switch stuck message. Nevertheless the AP panel would go offline and trims would fail.

Pulling the D15 and we don’t get the failure. Don’t have trims but no AP panel offline failure. So this allowed me to get the AP panel back on the network and make sure software was updated. We rang out both D37 connections on the back of both screens and both wiring harnesses for shorts to ground. All okay. Check AP panel and D15 wiring harness for shorts to ground. All okay.

While I had the D15 unplugged and could access the AP panel I turned off auto trim. Connected everything and rebooted and no failures. Everything works. Dynon doesn’t know how this is possible.

I turned auto trim back on and still no failures. Now we’re really stumped. Several boot cycles and 45 minutes online on ground power and no failures.

Sent them pics of network config screens per their requesting both with and without the D9 cables plugged into the AP panel. Waiting to hear back.
 

lancair360

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New theory from Dynon is that the network is overloading and kicking the AP panel (and somehow trim) offline. Even though we have software showing trim runaway.

Anyways....easy to pull some breakers. With two items powered down and not online on the network there is no failure. With one item powered down the failure happens in a couple minutes. With everything powered up it fails immediately.

At least we have a mode where I can fly the plane now. So I just turned off the autopilot circuit breaker switch cutting power to the pitch and roll servos and took off. Plane has a built race motor in it so it's awful to sit for weeks, gets really cranky. 20 minutes into the flight with no glitch I power up that CB switch and go another 20 minutes with no failure.

Landed, cycle power, no failure.

Did several other power cycles troubleshooting no fuel flow (pin 15 on the EMS D37 is dead, not giving volts to the transducer) and still had no failures.

Back to a computer / network issue. The slave screen is original and never had work. Serial number 2xxx and hardware version 1. I'm suspect of it.

But at least I can fly the plane now. Still got get fuel flow fixed, alerted Dynon to the dead pin on the EMS. If we swap out the EMS I will have replaced almost every component of the Dynon system in the last 3 years. All was installed in 2015. So average right now 6-8 years on the hardware before failures.

Still prefer working in the Dynon sandbox over Garmin any day of the week. And the customer service has been outstanding!! They've been a huge help these past 7 weeks and 100 emails back and forth (I counted).

Getting closer...I think.
 

Rhino

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Really appreciate you coming back with all the troubleshooting actions. That kind of stuff is really helpful to others who come here in search of information.
 

lancair360

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Oct 19, 2020
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Fixed the fuel flow. Not related to anything else.

Pin 5 on the Dynon D9 network cables is 12v. Passes through all components to power stuff and things. That power goes straight through the EMS to pin 15 for the sole purpose of powering fuel flow meter. Pin 5 on the back of the right hand screen was bent out of the way and not connected. My mistake from all the in and out of the panel I’ve been doing.
 
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