D10A - low voltage characteristics

[Andrew(Guest)]

Hi, I've been building a zenair for the past year and it's due for its test flight in a couple of weeks. I installed the D10A into the panel about 6 months ago and it seemed to be operating fine. It's wired to my avionics bus (and I have an avionics master to protect during start up and shut down) with a CB and I've noticed that when avionics master power is withdrawn it dims and goes into shutoff countdown. So far so good.

I was doing my compass swing today and half through the various moves the D10A just went blank. Couldn't bring it back to life at all. The compass swing involved a fair number of start ups and shut downs over a 30 min period. On a couple of occasions I forgot to turn the avionics master off before shutting down but I'd be surprised if that's to blame. Incidentally, I use the steinair harness and have the 9 pin connector for the EDC10A sitting free at the moment until the unit arrives in the post for fitting. It's been dangling for a while with no problems thus far.

I left it a couple of hours and tried it again and this time the D10A turned on, but gave a low voltage warning and the display kept flickering in brightness, sometimes looking normal and a few seconds later dimming again and then flickering. Adding avionics master power made no difference, it kept flickering away.

Any idea what this be? My engine's a rotax 912uls and there's no interference with the rest of my avionics from the engine turnover. I'll be pretty gutted if the unit's died on me as it'll take ages to get out of the (now rivetted and hard to get at) panel. And so soon before the test flight...

 

[dynonsupport]

Since you're getting a low voltage warning, it sounds like you have our optional internal battery installed. When the unit is running off of internal battery battery power and the battery is low (below 13 Volts) you will see the warning you describe. You can bring up all of the voltages that the EFIS measures under the "INFO" item in the menu system to verify this. There are a few potential reasons this can be happening - please give us a call at 425-402-0553 so that we can get a clearer picture of what you're seeing and help you troubleshoot quickly.

 

[Andrew(Guest)]

Thanks!  Will do - I'm going to see whether the problem reappears this weekend once I've recharged the plane's battery first though.  I wondered whether it might be loose wires at the EDCD10A socket end as it's definitely some kind of loose connection somewhere along the line, but the only loose ones are the ground wires there and they've not caused a problem before.  Bit of a puzzler!

 

[andrew(Guest)]

Well, did some ground runs to recharge the battery and slowly but surely the unit came back to life.  The screen was dim and every few minutes I put the brightness up to max and it got brighter and brighter each time until eventually it was back to normal.  At least I know it's battery low behaviour now!  Just got to get the connections to the OAT/EDC bit firmer to stop my OAT figures constantly varying...