Ironflight

Ironflight

VAF Moderator / Line Boy
Mentor
This is a long story ? you might want to get a coke?.and an aspirin....

As we finished up Louise?s RV-6 (AKA Mikey) panel upgrade two weeks ago, the only open squawk we had was that the two Dynon boxes ? the D-10A that she had installed a couple years ago, and the new D180 ? weren?t communicating over the DSAB bus. This was annoying, but not show-stopping, as quite frankly, when we designed the panel, we didn?t know that was a capability. However, I wanted to pursue getting this working, especially after flying a few times and trying to keep the two altimeter settings in sync ? it?s so much easier if you only have to do it once!

Now we actually had a small problem before the DSAB issue arose. After getting the panel powered up, and test-flying the plane for the first time, we deiced that with everythign working, it was time to bring both Dynons up to the latest software configuration. We hooked up the laptop, and the D10A uploaded without a hitch. Next came the D180 ? and spirit?s fell. The unit locked up in a really annoying way ? flashing screens that told us nothing, and no way to turn it off. Fortunately, it was the afternoon of a workday, and after talking to both Stein (who supplied the unit) and Dynon, and emphasizing that we were on a tight schedule, with Louise heading home in a couple days, we had a new D-180 on it?s way, overnight, Saturday delivery (at Dynon?s expense). The problem was diagnosed as a display board failure, and the new unit worked as soon as it went in. - - but we couldn?t get it to talk to the D10A?.

After some nice flying to round out the Holidays, Louise headed home, and I dove back into the troubleshooting. Eric, at Dynon, was a big help on things to try, but I ended up with a D10A that was stuck in a ?hung? donation that could only be resolved by pulling both the normal power and the backup battery connector. The problem was repeatable, so Eric put a new D10A in the mail ? again, Overnight, Saturday delivery. At the time, I was hoping to ferry the plan that weekend, but this was overcome by other events. The new unit arrived, and when we hooked it up, the same lock-up resulted when trying to configure the DSAB. AT this point, Eric suspected the D180, and suggested that I send BOTH units back to him, but due to the upcoming trip, and the fact that the plane was flyable, I elected to put further T/S on hold. Sometimes you just need to step away from the problem for a few days.

Unfortunately, it is hard for me not to want to solve a problem when I have an idea, so a few days later, I was underneath the panel, unbundling the wire harness to make absolutely sure that I had hooked up the DSAB lines correctly. Sure enough, blue to blue, green to green, and no shorts to ground. I tied everythign back up and sent Eric an email, suggesting that rather than me taking both boxes out and sending them to him, maybe he could take two known-good boxes, set them up on the bench, make sure they talked to each other, and send them to me. Within about an hour or two, he responded and said that I?d have them the next day, in time to install and test before my new planned trip date of this weekend! Now THAT is attention to the customer! (All of this shipping back and forth ended up on Dynon?s nickel by the way).

Sure enough, the package arrived at 10:00 this morning, and since I didn?t have to be at work until mid afternoon, I headed to the airport, greatly anticipating a working panel. I pulled the old units, popped the connectors on to the new ones, powered up and?..got the SAME results! OK, now we KNOW for sure that the problem is in the harness, but where? With the units out of the panel, I once again was looking into the business end of the DSUB connectors on the harness. Pin #4 on the D10A goes to pin #4 on the D180?.?Beeeeeeep? goes the meter. Pin #5 goes to Pin #5?.?Beeeeeeep?. OK, WHAT GIVES. They are connected, but won?t talk! Out came the magnifier, and the problem became clear. One of the d-sub sockets on the D10A harness (pin #4) looked different than the other ? in fact, it didn?t look like there was a socket in there. But I had continuity?!?! I put a probe in both sockets, and sure enough, the #4 socket was DEEPER. OK, all you techies, you know the answer now. I pulled the back shell off the connector and voila ? the socket was not fully inserted into the connector body. When I stuck a probe in to check continuity, it went in far enough to touch the recessed socket, and tested good. But when it was connected to the D10A, the pin wasn?t long enough to reach the socket, there was no connection, and no DSAB communication. The only way to figure this out was to look at it ? very closely. I pushed the socket in from the back with a tiny probe, listening for the ?click? and the first couple of times, it didn?t want to take. It finally stayed in, with more of ?soft? click, telling me that the retainer clip on that connector body was probably a little mal-formed. It did stay in however, I put the back shell on, connected everything back up and Bingo ? DSAB works!

More in part 2....
 
Part 2....

I tell this story in detail to make a few observations.

First, without Eric of Dynon?s cooperation, this would have been incredibly difficult to psych out. Having known good parts of the system is frequently the only way to find the problem. Getting replacement units in a quick and timely fashion sure helped me out, and went above and beyond what we would expect from big companies. Experimental aviation is now home to a number of very important small companies, and their attention to customer service is going to be the key to survival. Especially in the EFIS world, once a company gets their hardware sorted out and reliable, software becomes a question of matching or bettering the features of other companies, and customer service becomes one of the way that the end users can differentiate in their choices. I have been extremely fortunate with Grand Rapids (The EFIS I have in the Valkyrie) service in the past, and my experience with Dynon has now been excellent as well.


Second, In this case, I didn?t build either harness ? but I did connect them together. I went in and double-checked my work a couple of times, and verified with Eric how they should be hooked together. Probably the biggest contributor to making the problem hard to find was that the D10A harness had been in the plane ? and working ? for two years. I just assumed that it was all correct. The problem was that since there were no other Dynon devices at the time, so the two DSAB wires had never been used. Most likely, this socket had been a problem from the start, but since it wasn?t used, it didn?t make any difference. That?s a booby-trap just waiting to catch you! Make no assumptions that the work done before you is correct ? start from scratch. (?First, the earth cooled?.then, the dinosaurs came?.?)


Third, because of the rapid evolution of the devices, having the right manual is important, as there can be some confusion in how to hook up the DSAB lines if you se the older books. When I am actively troubleshooting or wiring, I like to pull just the pages of the books with connector drawings or pin-out lists to have in the cockpit ? it makes for less clutter, and allows quick access to the data you need to ring out the harness.

Fourth ? as is frequently the case, the problem was not one of being connected ?wrong?, having a broken box, or software that didn?t work. None of the obvious steps in a troubleshooting plan would have found the problem. It took thinking outside the box and looking closely for a physical error. As was mentioned in another thread yesterday, an errant aluminum chip can short out a radio. I?ve seen a sharp edge slice the outer sheath on a Coax line, creating a ground loop when the shield touched structure. Forcing ourselves to think outside the manual can be difficult, but that?s the art (and joy) of troubleshooting. Always ask yourself ?what haven?t I thought of??

Lastly ? leave yourself enough service loops to pull EFIS boxes clear of the panel in order to disconnect them. I didn?t give myself quite enough wire on this job, and while OK, it?s not ideal. I went for a very ?clean? harness, and came up about an inch or two short. Great for the thousands of hours of operation to come, but it makes the rare maintenance activities a little tougher. Hopefully, those should be rare from this point on out?.

Thanks again to Dynon for sticking with us on this project. As always, as customers, we?d prefer never having to call customer service for any company, hoping that we don?t have problems that require it ? but when we do, it?s nice to have a response like this.

Paul
 
Visual inspections..

Paul... being an Electronics Engineer, I always think the problems are primarily mechanical.

For all electronic troubleshooting, a very close visual inspection is my first step... since it's always mechanical...:)

I've seen the problem you described occur with Molex type connectors, and even BNC connectors. A good quality visual check for connectors is to ensure that all of the pins/sockets are in the same plane after a trial mating.

Personally, I like solder cups in my DB connectors so this won't happen...:)

gil A

PS ...after mechanical problems, I rate software as next in line before electronic problems...:D

PPS ... does Stein owe you a beer now?
 
Paul,

Am I reading your post correctly? If a DSAB wire breaks, it will lock up one of the DYNON units?
So much for redundancy.:rolleyes:

Paige
RV-8A (with a DYNON)
 
PaigeHoffart said:
Paul,

Am I reading your post correctly? If a DSAB wire breaks, it will lock up one of the DYNON units?
So much for redundancy.:rolleyes:

Paige
RV-8A (with a DYNON)
Click to expand...

Paige - the D10A locked up when we tried to configure the DSAB with the Blue wire not connected. As long as we stayed out of the DSAB configuration page, it seemed to operate independently just fine. Very annoying, yes, but probably low on the risk list, as you probably wouldn't be doing this in flight. BUt it is somehtign to remember.
 
Prescient

Hi Paul,

I'm on record as to having warned you about this, new years day on the "overhauling mikey's panel" thread. :eek:

Do I win anything? :D


Seriously, just about everyone who has built one of those connectors has been burned by a floating pin.

Best,
T.J.
 
Ted Johns said:
Hi Paul,

I'm on record as to having warned you about this, new years day on the "overhauling mikey's panel" thread. :eek:

Do I win anything? :D


Seriously, just about everyone who has built one of those connectors has been burned by a floating pin.

Best,
T.J.
Click to expand...

It's true. I immediately thought about your post when Paul told me the problem/solution today. Our bad. :eek:
 
Dynon support

Paul :cool: I'm sold - I'll be putting a Dynon product (D-180 most likely) into the panel of my RV-12. Your experience (as well as others reported recently in this forum) with Dynon support means a lot to me. Thanks for the report.
 
RE:Dynon/Eric/Fast Stack/Tim

Hi All

Paul thanks for the write up......Stuff happens.....I have lived by this motto and in some cases died by it: Successful people solve their problems successfully!!!!:D

Eric and I are near family. Over the month or two that I was putting my panel together Eric and Dynon in general really stepped up to my problem plate. One thing happened that is an example of their outsatnding customer service. Twice I made a mistake in the temporary wiring of elevator trim two the indicator wires of the EMS D120.......fried the D120 in the process. Sent It to them/they fixed the problem/patted me on the head/made me feel that it could happen to anyone (ya right)/ AND DIDN"T BILL ME.

All my Harnesses were built by the good folks at Fast Stack and their wasn't one problem. Lengths were to my specs/very clean/worked perfectly. I knew I could build them but I wasn't sure I could trouble shoot any problems I my miss wiring that I just knew I would make. My hat is off to all you good folks that did your own harnesses. Thus the few extra bucks to Fast Stack was worth it. Plus Tim has been very helpful and patient with me as I waded through the panel build.

I want to also thank Paul and Louise for their great write ups and info. It has been helpful, informative, and very entertaining.

So back to the cold garage to finish up the interior work.

Frank @ SGU RV7A interior last 1000000000000 details
 
Superb

Yes Dynon have been awesome to work with.

Don't you just love those "DOH" moments...:)

Frank
 
This stems from years of spark chasing

Years ago in a tax paying state far far away I was a deep sea marine electronics tech for a major electronics manufacturer.......

For years a secondary function of my job was to board heavy industry vessels and either install or repair gear on board.

This was an intensely frustrating job because the whole ship is literally a floating ground and sometimes you could get some really weird things show up.

In the course of the decade that I spent doing that, I developed an obsessive attitude towards weird problems. Every weird problem I have ever come across, that wasn't software related, ended up have the simplest solution in the world, like a pulled back pin or a single strand of a braided shield shorting across the MTR line of T/R up radar that I didn?t notice because of the gail force winds and driving rain that I was getting pounded with. This just added to the obvious frustration of having to sail around on some foreign flag vessel for two or three days eating God knows what and praying you didn't die from it.

I guess the point of all this is to say that perseverance and attention to detail are probably just as, if not more, important than your handy Fluke or your Dynon Instrument ELAB 008 computer based oscilloscope capable of a 80 MS/s sampling rate (shameless shelf promotion)

I give major kudos to Paul for his perseverance. His job was tougher than mine.

Eric
 
Paige,
As Paul mentioned, the lockups can only occur when you are doing the DSAB setup. This is something you only do once on the ground, so it isn't an issue in flight.

Once set up, shorts or wire breaks will not lock up the units, it will just break the sharing occurring over the DSAB bus.

We would prefer that it didn't lock up during setup either, and we'll be working on this, but we have done lots of testing with already setup units and have never seen a lockup.
 
Seeing is believing...

Thanks, Iron Flight, for the post.

I've now seen many, many posts of the high level of support provided by Dynon. I'm convinced that I want them in my airplane with me.
 
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