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Dynon Skyview HDX grounding/corrosion point

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I'm hoping someone can tell me where a Dynon Skyview HDX dual-display system is grounded in a 2018 RV-12 ELSA powered by a Rotax 912ULS engine.

I'm asking because after a year and a half of trouble-free operation, my Dynon HDX has been failing on virtually every flight, sometimes in as little as three minutes after takeoff, other times after a half hour. When it fails, the left half of my displays blink "ADAHRS Fail" and then "Attitude Recovering"; and the moving map says "Position Unknown." Several times, my altimeter and airspeed indicator have failed too. The altimeter has shown me at 50,600 MSL or below sea level, when I'm actually at 3500 or 4500 feet. And the airspeed indicator has shown me as fast 205 kts and as slow as 30 kts.

Dynon has been as helpful as it can be. It tried to repair my original ADAHRS, and when that failed on the first post-repair flight, it sent me a replacement ADAHRS and when that failed it sent me a second replacement ADAHRS. It also replaced my GPS. When none of these steps worked, Dynon concluded that I must have a short in the system, somewhere. But Dynon couldn't tell me where to look, because Dynon isn't familiar with the wiring pattern on an RV-12.

I took the plane to a shop with an avionics specialist. They didn't find a short, but did replace my battery which they said was failing, but that didn't fix the problem.

Last week, Van's issued a Service Letter telling RV-12 owners to do a Dynamic Propeller Balance. Van's said that if the balance is not done, damage could be done to the plane, and that the EFIS and Pitot systems may fail. I thought the Service Letter finally identifed my problem, and I had a Dynamic Propeller Balance done yesterday. I test flew my plane this morning, and the Dynon failed yet again, just three minutes into the flight.

The latest suspect is corrosion, because my plane is at Santa Monica Airport, less than two miles from the ocean. Two separate pilots have pointed to corrosion as the likely culprit, one of them suggesting that the likely spot is where the Dynon system is grounded.

I didn't build the plane, so I didn't wire it, and I don't know where the Dynon system is grounded, or even how the system is wired. If anyone can tell me where to look for the ground point, or where else to look for corrosion, I'd be most thankful.
 
Lon, you can buy the plans for the RV-12 on an inexpensive thumb drive from Van's. And a number of the sections can be downloaded for free on the Van's support web site.

Dave
 
Lon, you can buy the plans for the RV-12 on an inexpensive thumb drive from Van's. And a number of the sections can be downloaded for free on the Van's support web site.

Dave

Thanks Dave, I have the thumb drive and even the physical Kit Assembly Instructions. However, I can't find any pages that show where the Dynon Skyview HDXs are grounded, because the KAI is about building the plane, not about installing its avionics. The HDX installation manual doesn't show the RV-12 grounding point, because HDXs are installed in all kinds of planes. Unless I've simply overlooked the relevant pages, my issue has fallen in the crack between documentation for building an RV-12 and installing an HDX.
 
Per page 4-34 of the Skyview Installation Manual:

“To minimize the possibility of audio “humming”, a 16 AWG wire may optionally be
connected between the ground point for the intercom/audio panel/radio(s) and
SkyView display case(s). To attach the wire to the rear of the SkyView display, a 4-
40 x 3/16” long screw may be screwed into the threaded boss above the USB ports
on the back of the SkyView display.”

Page 4-14 shows the ground point on the rear of the HDX. I did install these during my build.

Hope this helps.
 
The failures are likely to be caused by a bad connection(s). I suggest that
you take every connection apart and inspect it, then put it back together.
 
Per page 4-34 of the Skyview Installation Manual:

“To minimize the possibility of audio “humming”, a 16 AWG wire may optionally be
connected between the ground point for the intercom/audio panel/radio(s) and
SkyView display case(s). To attach the wire to the rear of the SkyView display, a 4-
40 x 3/16” long screw may be screwed into the threaded boss above the USB ports
on the back of the SkyView display.”

Page 4-14 shows the ground point on the rear of the HDX. I did install these during my build.

Hope this helps.

This may help, Bob. I'm not having humming, so I don't need to ground the intercom/audio panel/radio to the HDX. I'm wondering which part of the plane is the grounding point for the HDX system. Is it the battery terminal, or part of the chassis? What I need to look for is a loose or corroded ground connection between the HDX system and whatever the ground point for the HDX might be.

Thanks, Lon
 
Grounding

Typically there will be a main grounding point for instruments on the inside of the firewall behind the instrument panel. This will in turn be connected to the battery negative terminal and the engine case. There may be multiple ground connections for radio, HDX's, audio board, intercom etc.

Have you noticed what system voltage is being displayed on the HDX when the problems occur?

Another item to check is the fuses, if they are the automotive blade type then it is easy enough to remove/inspect/replace.

Good luck, it is a pity the avionics shop couldn't track it down.
 
Typically there will be a main grounding point for instruments on the inside of the firewall behind the instrument panel. This will in turn be connected to the battery negative terminal and the engine case. There may be multiple ground connections for radio, HDX's, audio board, intercom etc.

Have you noticed what system voltage is being displayed on the HDX when the problems occur?

Another item to check is the fuses, if they are the automotive blade type then it is easy enough to remove/inspect/replace.

Good luck, it is a pity the avionics shop couldn't track it down.

Paul, Thanks. This is exactly the info I was looking for. I’ll look at those spots over the weekend. One of the failures occurred at 12.8 volts, but most occurred at 13.8 or 13.9 volts. There’s nothing significant about those voltages, is there?
 
Joe is correct. There are many sources of vibrations in a flying aircraft. Any human error in a non perfect crimp, or a wire that isn’t supported adequately, etc will be a candidate to fail at some unexpected time in the future.

It’s not hard to track down, but can be tedious.

Get the Dynon installation manuals. They will document what functions are on what pins. Using a voltmeter, do you have proper voltage on the power pins? Do you have continuity to ground from the ground pins?

When you state the EFIS fails, are you implying the screen is dark from lack of power? Or something else? If that is the case, it could be the power wiring or the ground wiring. The EFIS shouldn’t shutdown at the voltages you indicated. Usually they can continue to run a much lower voltages.

The easiest test is while you have the EFIS powered up on the ground, wiggle the wire bundles to see if that may cause a failure.

Otherwise, you will have to manually verify each connection in the circuit until you find the culprit.

It could something as simple that the pin isn’t inserted all the way into the db connector.

Make sure you take good notes through the troubleshooting. Knowing your systems intimately will help you greatly understand the situation if an emergency should happen in the future. Whomever built you aircraft should have provided a schematic for both power and data circuits. If they didn’t, reverse engineer the wiring and document it. I.e. pin 1 on db connector 1 goes to pin 25 on db connector 2.
 
Dynon Panel issues

Dynon avionics are and have been very reliable. I have sold and installed their avionics for 5 years and had only one issue and that was a SV-470 ADS-B "IN"
(Dynon's first version) Other than that NO issues reported to me.

As noted previously, the ground and all connections are of most importance for the system to continue to function properly. I once found a loose ground connector on my plane that caused panel flickering and shutdown, corrected this and no problems in 3 years.
If you have not checked all of the connections including both hot and ground connections I would start there.
If you do not have the wiring schematics for the Dynon avionics here are a couple of links to their installation manuals that may be helpful.
Best of luck and I hope the hear the problem was successfully resolved.
Marc

https://www.dynonavionics.com/skyview-documentation.php

https://www.dynonavionics.com/includes/guides/SkyView_System_Installation_Guide-Rev_AG-v15_4.pdf
 
Using a voltmeter, do you have proper voltage on the power pins? Do you have continuity to ground from the ground pins?

When you state the EFIS fails, are you implying the screen is dark from lack of power?

The easiest test is while you have the EFIS powered up on the ground, wiggle the wire bundles to see if that may cause a failure.

I don't know exactly what the avionics shop did while my plane was there (for 6 weeks). I assume they used a voltmeter to check voltage on the power pins and continuity to the ground from the ground pins. (And, yes, I do remember my flight instructor telling me that the word "assume" should never appear in a sentence about anything having to do with flying.) The avionics shop checked something with a voltmeter, because they concluded my battery had a dead cell, and they replaced it with a new battery, though that didn't help at all.

When the Dynon "failed," the HDX displays did not go dark. They continued to work perfectly. It was the information they displayed that made me say the system "failed." The failures were the altimeter, airspeed, GPS location, and attitude failures that I described in my original post. The data displayed during these failures was confirmed by the Dynon internal "black box" files, by ADS-B Out reports, and by ForeFlight -- all of which showed just what the HDX displays showed.

I have wiggled the wires connected to the HDX displays, but doing that did not trigger any failures.

Thanks Bob. I will follow through with the manual verifications that you and Joe have advised must be done. Because I'm not the builder, and don't even have a hangar in which to work (my plane is tied down outside), I've been looking for another avionics guy near Santa Monica who is able and willing to do the work. I pay my bills promptly. But mechanics and avionics specialists are so busy here in Southern California that I'm struggling to find one that will take on the job or even return my calls.
 
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Dynon avionics are and have been very reliable. I have sold and installed their avionics for 5 years and had only one issue and that was a SV-470 ADS-B "IN"
(Dynon's first version) Other than that NO issues reported to me.

As noted previously, the ground and all connections are of most importance for the system to continue to function properly. I once found a loose ground connector on my plane that caused panel flickering and shutdown, corrected this and no problems in 3 years.
If you have not checked all of the connections including both hot and ground connections I would start there.
If you do not have the wiring schematics for the Dynon avionics here are a couple of links to their installation manuals that may be helpful.
Best of luck and I hope the hear the problem was successfully resolved.
Marc

https://www.dynonavionics.com/skyview-documentation.php

https://www.dynonavionics.com/includes/guides/SkyView_System_Installation_Guide-Rev_AG-v15_4.pdf

Thanks for these links, Marc. I had the Installation Guide, but the schematic diagram is much easier to read than the one I had.
 
The first place that I would check is at the ADAHRS. Like Bob Leffler wrote,
make sure the D-Sub pins are seated properly. Unplugging and plugging in a
few times will wear away corrosion. Since the plane is located in a corrosive
atmosphere, some type of chemical spray might help.
 
The first place that I would check is at the ADAHRS. Like Bob Leffler wrote,
make sure the D-Sub pins are seated properly. Unplugging and plugging in a
few times will wear away corrosion. Since the plane is located in a corrosive
atmosphere, some type of chemical spray might help.
Joe, The ADAHRS is in the plane’s tail, behind the baggage area bulkhead, and VERY hard to get to, so I had a professional mechanic replace it. Also, the ADAHRS has been replaced three times since the problem began, so if there was corrosion back there, I hope the mechanic would have seen it, and by the third replacement I hope the mechanic would have been especially careful to get the pins seated properly. Or are you talking about the D-Sub pins at the cockpit/panel end of the ADAHRS wiring harness?
 
Lon, I was thinking of the ADAHRS end of the cable when I posted above. But
you are correct that the problem could be at the forward end of the cable. Do
not assume that the mechanic carefully inspected the D-Sub connector unless
he was specifically asked to do so.
_I helped a friend troubleshoot his ADAHRS new installation. To rule out the cable,
I made a temporary test cable using CAT 5 Ethernet cable and new D-Sub connectors.
Ethernet cable contains the required 4 twisted pairs. Page 25-2 of the
SkyView HDX System Installation Manual - Revision E shows the pinout.
My friend's ADAHRS worked fine using the test cable.
It turned out that my friend had wired his D-Sub connector incorrectly, pins reversed.
 
Lon, I agree with Carl. Since u are not a builder this has to be overwhelming. An A&P, even an electronics Guy, will have difficulty as u have experienced. Bruce has a 9A with a Dynon panel. He has upgraded other RVs for others. Probably your best bet, and best $$$ spent.
 
Lon, got your PM. Let's talk! Sure sounds like a communication problem with the ADAHRS and/or GPS.
 
Glad that somebody is able to help, it will be interesting to hear about what you find. Must be something amiss on the Skyview Network but puzzling that the display internal diagnostics don't seem able to provide more info?
 
I don't know exactly what the avionics shop did while my plane was there (for 6 weeks). I assume they used a voltmeter to check voltage on the power pins and continuity to the ground from the ground pins. (And, yes, I do remember my flight instructor telling me that the word "assume" should never appear in a sentence about anything having to do with flying.) The avionics shop checked something with a voltmeter, because they concluded my battery had a dead cell, and they replaced it with a new battery, though that didn't help at all.

When the Dynon "failed," the HDX displays did not go dark. They continued to work perfectly. It was the information they displayed that made me say the system "failed." The failures were the altimeter, airspeed, GPS location, and attitude failures that I described in my original post. The data displayed during these failures was confirmed by the Dynon internal "black box" files, by ADS-B Out reports, and by ForeFlight -- all of which showed just what the HDX displays showed.

I have wiggled the wires connected to the HDX displays, but doing that did not trigger any failures.

Thanks Bob. I will follow through with the manual verifications that you and Joe have advised must be done. Because I'm not the builder, and don't even have a hangar in which to work (my plane is tied down outside), I've been looking for another avionics guy near Santa Monica who is able and willing to do the work. I pay my bills promptly. But mechanics and avionics specialists are so busy here in Southern California that I'm struggling to find one that will take on the job or even return my calls.

You’ve provided some really valuable information. Did your engine data remain displayed? With the gps did the magenta line on you map disappear or just the lat/long data stream?

Many of the Dynon connections are through the sv-network. It’s looking like that may be your common denominator. The adahrs are on the sv-network. The flight plan data from the gps (magenta line displayed on your map) comes through the Sv-Arinc box, which is attached to the sv-network. The engine sensors are also connected via the sv-network, which is why I asked if they were affected. The gps lat/long data is a rs-232 connection, which is direct to the EFIS.

Identification of the specific data the is affected and then knowing how that data gets to the EFIS is going to be key to isolating the root cause of the problem.

While there are great avionics shops out there, many are also jacks of all trades and master of none. Because of the volume of different solutions out there, some shops just don’t keep up with all the various vendors products.

I would focus first on a bad crimp, intermittent open circuit, pin not completely inserted, etc, on the cable going from your EFIS to your sv-network hub. The odds of multiple connections going into the sv-network being bad are slim, so that’s why the single cable between the hub and you EFIS would be a good starting point.

Are your cables the white ones with black plastic shells from Dynon, or did somebody custom make the wiring harness? I’ve never seen an issue with the Dynon cables, but that doesn’t mean that can’t have an issue. Taking the shells of the db connectors isn’t that difficult, but if you’ve never done it before it could be overwhelming. Is there somebody in your local EAA chapter that can mentor you?

If you have two EFIS, then swapping the sv-network cables between the two EFIS would be another great troubleshooting step. The the problem stay on the same screen or did it move with the cable swap?


Even if you don’t understand all the information right away in the install manuals, I highly recommend getting a copy and reading it. It will help you understand your systems better.
 
You’ve provided some really valuable information. Did your engine data remain displayed? With the gps did the magenta line on you map disappear or just the lat/long data stream?

Many of the Dynon connections are through the sv-network. It’s looking like that may be your common denominator. The adahrs are on the sv-network. The flight plan data from the gps (magenta line displayed on your map) comes through the Sv-Arinc box, which is attached to the sv-network. The engine sensors are also connected via the sv-network, which is why I asked if they were affected. The gps lat/long data is a rs-232 connection, which is direct to the EFIS.

Identification of the specific data the is affected and then knowing how that data gets to the EFIS is going to be key to isolating the root cause of the problem.

While there are great avionics shops out there, many are also jacks of all trades and master of none. Because of the volume of different solutions out there, some shops just don’t keep up with all the various vendors products.

I would focus first on a bad crimp, intermittent open circuit, pin not completely inserted, etc, on the cable going from your EFIS to your sv-network hub. The odds of multiple connections going into the sv-network being bad are slim, so that’s why the single cable between the hub and you EFIS would be a good starting point.

Are your cables the white ones with black plastic shells from Dynon, or did somebody custom make the wiring harness? I’ve never seen an issue with the Dynon cables, but that doesn’t mean that can’t have an issue. Taking the shells of the db connectors isn’t that difficult, but if you’ve never done it before it could be overwhelming. Is there somebody in your local EAA chapter that can mentor you?

If you have two EFIS, then swapping the sv-network cables between the two EFIS would be another great troubleshooting step. The the problem stay on the same screen or did it move with the cable swap?


Even if you don’t understand all the information right away in the install manuals, I highly recommend getting a copy and reading it. It will help you understand your systems better.

Bob,

Good questions, all.

My engine data does remain displayed. The gps magenta line disappears. I don't remember what color the cables are, but the builder bought the wiring harnesses from Van's. The cables must have been good to begin with, because the avionics were perfect for more than 2 years. The problems that appeared without warning show up in identical fashion on both displays. The altitude error shows up on FlightAware, as well as on the HDX displays. And the gps failure shows up on ADS-B Out reports as well as on the displays.

I'm working now with Bruce H, and his plan of attack is quite similar to yours, proving that "great minds think alike."

Thanks,
Lon
 
Bob,

Good questions, all.

My engine data does remain displayed. The gps magenta line disappears. I don't remember what color the cables are, but the builder bought the wiring harnesses from Van's. The cables must have been good to begin with, because the avionics were perfect for more than 2 years. The problems that appeared without warning show up in identical fashion on both displays. The altitude error shows up on FlightAware, as well as on the HDX displays. And the gps failure shows up on ADS-B Out reports as well as on the displays.

I'm working now with Bruce H, and his plan of attack is quite similar to yours, proving that "great minds think alike."

Thanks,
Lon

Did you and Bruce H get this resolved, and what was the solution to the problem?
 
Check this

Lon,

I have done quite a few installs, and have designed my own interconnect board. When I see a problem, I do a simple check. When you have the error, go to the Network Status page in setup up.

SkyView Network has redundancy and error detection features which allow it to detect and annunciate module and SkyView Network wiring faults. In the event that SkyView reports a problem with an ADAHRS, EMS module, autopilot servo, or a problem with the “standby network”, this NETWORK STATUS page will provide more information about the nature of the problem.

You can do this inflight. Go into setup, this will take you into the inflight setup screen. Select the bottom line which will take you into the ground setup screen. Then get into the Network Status screen. With the error shown, press the 2 and 7 button, and it will take a screen shot and save it to your thumb drive if installed, so when you get back on the ground, and if the problem goes away, you know where you need to start looking.

During install, if you simple swapped the white/blue with the white/green wires, it will show you the error in network status.

With my board design, I have a long SkyView Network test cable, and I just unplug the installed Network cables on both ends, replace it with my test cable and see what’s happens. If it starts working, I know the problem is somewhere in the installed cable, and then start checking the connectors on each end.

Hope this might help, and good luck. Report back what you find, as it might help someone else if they find they have a similar problem.

Brian

After rereading some of your posts, you might just have a screen with corrosion problems within the screen.
 
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Did you and Bruce H get this resolved, and what was the solution to the problem?

No, Bruce and I have not resolved the problem yet. Bruce helped a lot, via phone and text, by steering me towards the likely problem, and letting me know what to do to find and fix it. The problem is probably a short in the SkyView Network, possibly in the vicinity of the Van's Controller (i.e., the hub that SkyView components plug into). The exact location of the short is still unknown, though, because one possibility is that it's somewhere along the wires from the ADAHRS in the tail of the plane to the Controller in the avionics bay in the cockpit. The ADAHRS wiring harness is suspect, because the wires in that harness are zip-tied to a rib in the tail, to the sides of the tail and probably to the floor of the fuselage under the seats. This is the way the KAI tells builders to do it. But I've been advised that zip-tying to metal can cause chaffing and thus shorts. Searching for the short has been tough for me, for reasons I explain in my next post just below.
 
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Thank you very much to all of you who have offered me suggestions and wisdom. I now believe the problem is a short somewhere in the SkyView Network, and all would be good if I could find it and correct it. Alas, therein lies the rub. The SV Network includes several wiring harnesses, each of which has several to many individual wires. In my plane at least, the wires connected to each D-Sub Connector are bundled together with zip ties, and those bundles are zip tied to other bundles. This makes everything in the avionics bay secure, but it makes it impossible to inspect most of the wires, and even harder to inspect the D-Sub pins. I know this, because I removed the top of the avionics bay to get a good look at the wiring, and realized that in order to do a close inspection, I'd have to remove the wiring from the plane entirely, in order to look at it on my desk at home under a bright light. (I don't have a hangar. My plane is tied down outside.) I began by unplugging Connectors from the Van's Controller box, before looking carefully to see where the wires go from there. After getting the Connectors unplugged, I saw (too late) that they went through grommets that were too small for the D-Sub connectors to pass through. I figured out how to get one of the grommets out of the surrounding metal J-slot, but in doing so, I broke the power wire to the fan on the co-pilot side of the avionics bay. Fixing that wire requires new clips and I'm waiting for those to be delivered; but in the meantime, that made me worry about what else I might break trying to get the wiring harnesses home. To compound things, I then realized that some of the wiring goes through grommets into the engine compartment where they are permanently soldered onto things there, like the GPS and (I think) engine monitoring sensors; so those wires can't be removed from the plane. Getting a good look at the ADAHRS harness required me to remove the pilot's seat, and I did. So, by then, my plane was practically back to being a kit, and I was getting worried I wouldn't be able to reassemble it properly, and that I was -- or was about to become -- the proud owner of a batch of airplane parts suitable only for sale to a salvage company. Fortunately, I'm pleased to be able to report that I was able to get everything reassembled properly. But I'm just as far from finding the short as I was at the beginning. :(
 

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Hi Lon,
Dang, this must be getting quite frustrating!

The electrical system for your RV-12 is quite integrated and complex, according to the wiring diagram, assuming it has been built according to Vans plan:

https://www.vansaircraft.com/wp-con...RV-12_ULS_SkyView-After-08-25-11_12-18-18.pdf

According to this wiring diagram, the ADHARS is connected via a 9 pin connector. The autopilot servos are also hooked into this loom, which finally connects to the Vans hub via a 37 pin plug. So the fault could be anywhere, I don't think it will be trivial to find it, unless there is a visually obvious break or chafe somewhere.

I certainly wouldn't remove any harnesses from the aircraft at this stage! Post #27 by Pdtofly has some good suggestions for testing in-place. Otherwise about the best you could do on your own may be to unplug and replug all of the accessible Dsub plugs that carry the Skyview Network, just in case the cause is a poor connection between pins somewhere.
 
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Lon-

Most of the ADAHRS wiring goes through grommets as you pointed out .... however, as a builder I can tell you the first two locations I would look for chaffed ADAHRS wires are in the tail cone.

Have a look at drawing 31B-20 figure 1 .... you can see that the ADAHRS wires enter the tail cone from the center tunnel and bend left towards the left side of the tail cone then make a bend aft and swoop up onto the J-stiffener. I feel this is potential trouble spot #1.

When assembling, I felt where the wires jump up onto the J-stiffener would be a possible area for wire chaffing and protected the wires at that location using a piece of split tubing as can be seen in the following photo link.
http://4.bp.blogspot.com/-4E7VX0IV1HI/VVXg30o2zBI/AAAAAAAAI3w/8lD3nAm1dro/s1600/DSC09489.JPG

The next area I would have a close look at can be seen on drawing 31B-21 figure 1. The ADAHRS wires are wire tied onto the F-1208 frame. If care was not taken installing the wires they could rub on the edge of the F-1208 frame.

My last suggestion for you would be to have a very close look at the wiring transition above the rudder pedals as can be seen on drawing 31b-25 figure 3.

Remove F-12125 and have a VERY close look at this area .... and while in that area remove the wire tie from F-12125C (both can be seen in figure 3). The amount of wires running under F-12125 makes it very difficult to correctly install F-12125 without pinching wires. It is like trying to stuff 5 lbs of cra* into a 3 lb bag. Note: In this area I placed some heat shrink tubing over the threads of the screw that secures F12125 so the wires can't chafe on the screw's threads when the screw is in place.

All the above areas are potential problem areas and merit a good looking over.

Good luck,
 
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Open circuits are much more common than shorted circuits. But in either case,
substituting another cable will tell you if the existing cable is good or bad.
You can buy one from DYNON. Instead of trying to fish a new cable through the
airframe, just run it through the passenger and baggage compartment
temporarily for testing purposes.
 
Dynon cable?

Open circuits are much more common than shorted circuits. But in either case,
substituting another cable will tell you if the existing cable is good or bad.
You can buy one from DYNON. Instead of trying to fish a new cable through the
airframe, just run it through the passenger and baggage compartment
temporarily for testing purposes.

I'm not sure that buying harnesses from Dynon would work (I may be wrong!) because the existing harnesses are by Vans, not Dynon, and the network "hub" is also by Vans, not Dynon. Based on the wiring diagram it looks like the the plugs and harnesses are quite different and not compatible, it would seem?
 
You are correct that most of the RV-12 is wired with Van's wire harnesses.
But Dynon components must be wired per Dynon manuals, especially the Dynon network.
 
Thanks again to all of you who shared your knowledge and experience with me. I tried many of your suggestions — all that I had the tools, ability and confidence to try. I wasn't able to do everything that was suggested. But I did get a lot of phone, email and in-person help from Bruce H. Indeed, Bruce drove up to Santa Monica Airport, and spent four hours with me inspecting the avionics components and wiring, looking for the cause of the problem. We did not find it. Based on the advice I received here and elsewhere, I think the avionics can be fixed by someone who has the right tools, a hangar to work in, and the willingness to treat the task as a hobby. But I am not that person. So as much as I loved flying the plane, I have decided to sell it, as is, where is. I've just posted the plane's details, and the terms on which I'm offering it for sale, in the Classified section of VansAirforce. If you might be interested in buying it, take a look. Thanks again, and I'm wishing all of you a happy, healthy and eventually virus-free 2021.
 
Did you ever go through with disconnecting both HDX panels and sending them back to Dynon to run diagnostics checks for internal shorts or corrosion on the circuit boards / switches?

Sounds like you and Bruce H have exhausted all the other options, for trouble shooting.


Ownership of an Experimental LSA plane by someone not too mechanically or electronically inclined is probably not the best idea. A S-LSA RV-12 might be a better choice, along with a really good AP familiar with RV-12 builds and equipment. Or, just rent a plane.

2 screens doubles the load on the electrical system, which is already pretty heavily taxed when also recharging the battery, on the Legacy RV-12's or any RV-12 with the 912 ULS motor, as well as doubling the amount of points of failure for electrical corrosion on switches and circuit boards inside. You have fans mounted to the back of those electronics, to keep things cool. You fly over salt air, over any ocean, and you are pumping salt onto the circuit boards, push switches, everything. Never good for any electronic devices, salt air is corrosive to lead and tin that's solder on the circuit boards.

I would think that there would be some RV electronics savvy repair places that see these kinds of problems, also over at KCMA, they are near the ocean too.
 
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Lon,

Just to follow up and summarize to others what we looked at. The wiring harness is stock Van's. We took off all of the various connections at the wiring hub (Van's design/mfg, aka the control module). All of the connections looked fine. No bent pins observed. No pins loose or not seated properly. The 4 wires that head off to the GPS antenna were fine. Solder sleeves were used to connect up a replacement GPS antenna. From looking at the flight data on SavvyAnalysis, the GPS just randomly goes dark (power? ground?). When the GPS goes offline, it will sometimes come back rapidly, or it will additionally take offline something else like the VERT SPEED, or ALTITUDE, or IAS, etc. When this happens, there is no Skyview Network alert. What is odd is that the ADAHRS data and the GPS data are on completely separate circuits (SV network vs. EFIS Serial port).

We looked at the wiring all the way from the front panel back to the ADAHRS unit. No chafing, or pinched wires. Connectors looked fine. No obvious corrosion anywhere. This wiring was correctly installed and tied up with zip ties and was not rubbing anywhere.

We checked the SETUP menus and could see that all of the Skyview network devices were present and communicating. The GPS is on Serial port #5 and it was putting out good data (as we sat on the ground). We tried to wiggle things to see if anything was intermittent, but didn't notice any issues.

We took off all of the connectors at the control module hub and examined the box from the outside. There is a sticker on the box saying not to open and if missing it would void the warranty. We did clean it with some electrical contact cleaner on the off chance there might be something inside causing a short. There is not a lot going on in this Van's control module hub. It is a circuit board that distributes various signals to different connectors/harnesses. There are also some small potentiometers on the box that allow you to adjust things like headset volumes, etc. My only thought is that this hub might be the culprit, since it is the common denominator, and the wiring elsewhere looks just fine. Has anyone else with an RV-12 experienced any issues with the control module hub from Van's? Swapping out a new box here is a trivial task and would be something else to try before giving up.

As Lon has mentioned, the ADAHRS and GPS have been swapped out without any difference, so IMHO it most likely is NOT a Dynon component issue. My recommendation was to go fly it after we examined and reseated all of the connectors. Looking at flightaware, I don't see any flights after November and I was there in December. My offer stands to do some further troubleshooting if you can bring it down to Ramona airport. We didn't really take a look at the CHT, but I think it is likely a bad probe. Swapping Left to Right would confirm this.
 
I just got back from Steinair with my RV12. I had loads of problems with the two Dynon HDX panels that I have. I was at my wits end trying to find someone to work on them. I finally called Stein and they completely fixed the problem. I live in Kentucky, so it was an effort to get there. Worth the trip!
 
Lon,

If you like the airplane, and aside from this issue, want to keep it, why don't you take Bruce up on his offer to troubleshoot some more at his hangar? I am sure someone else would be glad to fly your airplane to Ramona, if you aren't comfortable doing so.

Bruce is very capable of troubleshooting the system and getting it back in working order.

We've ALL had frustrations with our RV's, but usually one the issue is solved, things improve and we go back to enjoying our aircraft.
 
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