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HDX will not power on

Flying Canuck

Well Known Member
Patron
Let me first start by saying - yes, I will open a ticket with Dynon. It's the weekend so I thought maybe someone here had some experience with this issue while I wait for Dynon to get back to the office.

I took a 50 minute flight to High River today to meet up with an instrument pilot that I was connecting with to see about finishing my hours requirement. That's not all that relevant to the issue. When we went to go for a flight, I turned the master on and found that the HDX display did not start up (VP-X with the HDX as the startup EFIS). It didn't start up by holding the power button (button 1) either. I checked to make sure all of the connecters were securem which they were.We pulled the plane into the hangar and let it cool down while we went for a very enjoyable flight in his plane (RV-7A). Very strange flying from the right seat.

When we returned I checked again and still found the HDX would not power on. We pulled the harness and confirmed voltage on both power pins and ground on both ground pins at the harness. I then removed connections and usb devices one at a time until the D37 was the only one left, checking the power up each time. No joy.

I found something online that said to check the status lights on the ethernet ports. Nothing lights up.

Finally we tried powering up on the backup battery with the master off. That worked. Twice. Second time I left it on and flew my plane home. The entire flight it was annunciating that I was on backup battery (with the master on) and for the last 20 minutes it was telling me that my back battery was low - so not charging. There are no other issues with any electrical device.

I've never had any issues like this with the panel. This seems to be to be a problem with the power circuit on the HDX. Anyone run into this and can share their experience in getting it fixed? This pretty much ends my hopes of getting my instrument rating done before my trip to the other coast on Aug 15. It also casts doubt on that trip, so any ideas is appreciated.

I did capture diagnostic logs and will send to Dynon.
 
Claude - I'm sorry to hear this has happened to you as I'm sure it's both frustrating and most unsettling. I'm glad to see you have documented your symptoms here such that others might benefit from your experience. To that end, I hope you will post back with Dynon's response and corrective actions.
 
I would look at the VPX before the SkyView HDX. Just because you have voltage on the pins does not mean the VPX will power it up.

Carl
 
Sounds counter productive, but have you considered a switched or temporary power bypass - HDX direct to 12 volt buss? If the EFIS curcuit tripped in the VPX, might be only way to access the VPX controls.
 
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That's something a lot of people don't realize about the VP-X...If that particular circuit is commanded OFF, either through an overcurrent condition or manually, it can still show bus voltage on the pin with no load on it, but if you put a load on that pin, indicated voltage will fall to zero.

From the VP-X manual:
Vertical Power said:
When I measure a pin that is “off” with a digital multimeter, I get a voltage reading. Is this normal?
Solid-state switches have a characteristic called stray or phantom voltage that will read slightly below bus voltage on a power pin even when that pin is off. Don’t worry, it won’t cause sparks or arcing. There is no “power” behind the voltage, it is simply an artifact of the solid-state switches (a specialized transistor). In order to measure voltage correctly, there needs to be a load on the pin, like a test lamp, when taking measurements. If the pin is off, the voltage will be zero when there is a load on it. If the pin is on it will read at bus voltage when there is a load on it.
 
EFIS power up

Claude,

I have an Advanced Flight 5500 EFIS with the Skyview network and had these exact symptoms. The EFIS would not power up from the main bus and the only way I could get it on was to force it to power up on the backup battery by pushing a specific button on the AFS EFIS. I did some troubleshooting and what I discovered was a loose crimp on the power wire coming into the EFIS circuit breaker. I had enough wire on that line to put a new crimp on and it has worked flawlessly ever since.
 
That's something a lot of people don't realize about the VP-X...If that particular circuit is commanded OFF, either through an overcurrent condition or manually, it can still show bus voltage on the pin with no load on it, but if you put a load on that pin, indicated voltage will fall to zero.

From the VP-X manual:

Okay, now I'm wondering if I've just sent my HDX away for repair needlessly. The voltage was slightly below bus voltage when I checked it. I can check other circuits powered by the master switch to see if they get different voltage. I had no other electrical issues on my flight home, so it would be isolated to this single circuit. I'll have to check it out tonight. I can try to add a load to the circuit as well. If this phantom voltage is from the ECB, it wouldn't be a wiring issue, would it?

I'll have a look at the possibility of a bypass connection as well.

I had forgotten about it until Dynon told me, I sent this same unit back to them for repair of a power issue 3 years ago - before my first flight. I don't have any record of the problem or the repair since it was arranged over the phone and I don't remember any details, but there is history.

The unit is in transit to Dynon right now, arriving tomorrow. They've told me that they can turn it around quickly, so I should have it back next week in time for my departure for the east coast on the 14th. Guess I need to make sure that if it's a problem with the VP-X and not the HDX that I get a workaround or fix in place.
 
Well I guess my HDX is on an unnecessary trip to Dynon. Went out and check the harness voltage and the bus voltage, bus was a little over 13, harness was 7 and 3.5. Traced my wiring found that it was pinched in an avionics tray - not damaged, but in an awkward spot. I moved the wire out of there and checked voltage again, bus voltage. I rerouted the wires, inspected them for chaffing and found none. I checked voltage one last time and found it to be still giving bus voltage.

Thanks for the tips everyone, that really helped. Now where were you when I first posted this question, I could have avoided sending the HDX out in the first place. Just kidding of course, I'm pleased to have found the issue.

I'll be calling Dynon in the morning and asking them to not bother opening the box when it arrives and send it back to me.
 
Traced my wiring found that it was pinched in an avionics tray - not damaged, but in an awkward spot. I moved the wire out of there and checked voltage again, bus voltage. I rerouted the wires, inspected them for chaffing and found none.

I'll be calling Dynon in the morning and asking them to not bother opening the box when it arrives and send it back to me.

Pinching wires doesn’t reduce their current carrying capability - unless you broke some of the strands. They might now look better as the insulation is holding the strands together where they broke, but I’d replace that wire.
 
Pinching wires doesn’t reduce their current carrying capability - unless you broke some of the strands. They might now look better as the insulation is holding the strands together where they broke, but I’d replace that wire.

You are most likely right about that and it's an easy fix. It's also possible that I didn't see the damage. I highly doubt that the damage was such that the wire contacted the tray - that would have been a short - but it would need to have some sort of damage to have that effect. I have plenty of wire that was nowhere near the pinch and I'll use the opportunity to bypass the terminal block that I ran it through as it serves no real purpose.
 
Here's an update on this - summarized by one statement: Dynon Support is amazing.

Dynon received my HDX last Thursday, they didn't want to just ship it back unopened (I had found an electrical issue in my plane that explained the issue that I had returned it for). They had one modification that they try to do to all early HDX units that they thought they'd do while they had it. The next afternoon they shipped it back to me. Today I got the $0 invoice for the work and it indicated that they were shipping me a refurbished unit. They found something not quite right and rather than fix it, they sent me a different unit because I had a time constraint. They wanted me to have something with extended longevity.

Even though I am a year out of warranty, Dynon did not charge me anything, not even return shipping. Well beyond what I expected.

I don't have the replacement unit back yet, it will arrive on Wednesday. This will give me ample time to make sure my plane is ready for the trip to the east coast this weekend.

While I'm unlikely to become a two-time offender/builder, Dynon has earned my loyalty for a long time with this service.

Thanks Dynon!
 
Here's an update on this - summarized by one statement: Dynon Support is amazing.

<snip>

Even though I am a year out of warranty, Dynon did not charge me anything, not even return shipping. Well beyond what I expected.

I don't have the replacement unit back yet, it will arrive on Wednesday. This will give me ample time to make sure my plane is ready for the trip to the east coast this weekend.

While I'm unlikely to become a two-time offender/builder, Dynon has earned my loyalty for a long time with this service.

Thanks Dynon!
Now I've gotta ask the question, what would this have "cost" Dynon? Couple hundred bucks in the employees time? Maybe a grand to fix whatever was wrong with F C's screen? They could've just sent it back but they didn't...

But knowing you can (will) get that kind of service in the Experimental world - and it isn't just from Dynon either - makes me wonder why people still persist with Certified aircraft!

That being said, I'm hopefully going to be looking at a Comanche 260B (don't hate on me, the KRviatrix won't let me build a -10 and it's the closest to a -10's performance I can find!) next week to replace the -9, and if it ends up in our hangar it'll be getting the full Dynon treatment too...
 
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