Rv12 regular buzzing

[mike_newall]

Just test flown our RV12, 2017 Vans software install on Dynon Skyview HDX.

All set up fine, seems OK but have an annoying regular buzzing noise through the intercom.

After checking, we think this is the cause.

Because the flight testing is being done at a non fuelled airstrip, I decided to use the direct reading gauge for flight testing and then go to a gassed airfield with min fuel, drain down and then be able to safely dispense fuel gallon by gallon.

Now, the annoying buzz is directly in time with a warning thingy on the Dynon and I am now wondering if you have set up two levels of alarm - low level attention getter and OMG - yo, gunna perish boy ! It is the only uncleared alarm because the Dynon thinks I have no gas !

 

[Raymo]

You can disable the audible alarm until your fuel sensors are calibrated. I did the same with my CHT warning due to occasional issues with one sensor that I plan to fix with different connectors.

 

[mike_newall]

OK, Now calibrated the tank, the warning has gone away and the buzzing continues.

Any other suggestions ?

 

[Raymo]

I suspect you have a widget configured that is triggering the alarm but may not be visible on the EMS part of the screen.

 

[rswalden]

Just test flown our RV12, 2017 Vans software install on Dynon Skyview HDX.

All set up fine, seems OK but have an annoying regular buzzing noise through the intercom.

After checking, we think this is the cause.

Because the flight testing is being done at a non fuelled airstrip, I decided to use the direct reading gauge for flight testing and then go to a gassed airfield with min fuel, drain down and then be able to safely dispense fuel gallon by gallon.

Now, the annoying buzz is directly in time with a warning thingy on the Dynon .......

You have the gain set too high on your AV-50000A for the Skyview audio input.  There are input potentiometers on the side of that unit that control volume from every input (radio, intercom, stall, etc).  I had the same issue... Turn up audio output on the SkyView (the one that repeats "Dynon Skyview") to 100%, then turn the input to the AV-50000A counterclockwise with a very small flat screw driver.  That will fix the problem.

 

[mike_newall]

Tried altering the gain, no effect. Turned off every alarm, no effect. Tried earthing the Dynon case direct to intercom, no effect. Pulled each CB, no effect.

The buzz is at exactly 1 second intervals and corresponds with the seconds on the clock.

We have two identical installs on two identical RV12's built as per plans and they both have the same regular buzz.

I cannot access any of the individual cables, nor should I have to as it all came plug and play from Vans with the Stein test coupons for each cable.

Any other suggestions ?

 

[DHeal]

Out-of-the-box here but could the one-second pulsations be associated with strobe/lighting wig-wag electrical interference?

 

[mike_newall]

We are troubleshooting without wings on, so not connected.

 

[Raymo]

The one second interval could be related to your transponder. There have been cases where the transponder output was being picked up by the ELT, which has a buzzer.

Try pulling the transponder fuse/breaker and see if the noise goes away.

 

[mike_newall]

Have....

Doesn't

 

[Dynon]

Is there ANYTHING at all that is messaging or alerting on button 8 when you're hearing this? The only other thing I can think of is that there's an EMS alarm light line output that will fire with alarms. If that line was going somewhere that wasn't a light, and there was some alert firing, I wonder if you're hearing that line go open and closed (it's a switch to ground that you'd put a light on the other side of). I don't remember the interval of when that line opens/closes, but that buzz seems pretty sync'd with the alerts (from the earlier video).

 

[mike_newall]

That is interesting.
We have no EMS light as it alerts through the Skyview.
I will have a look today.

 

[mike_newall]

So......

We have closure. Dynon Support were very good, Jeff engaged and chatted about the issues. The AV50000 was dialled down on the pots, not any real change. He agreed to send some noise filters and they were fitted to the second aeroplane. Silence ensued, which was nice.

However, when I installed exactly the same filter on the first aeroplane, the buzzing stayed

Now I was perplexed.

I thought it through, fiddled with various bits and pieces and then spotted a label next to the squelch on the intercom that said mute. I pressed it and the buzzing stopped.

OK..... I have no idea.

We have 2 identical aeroplanes, built at the same time, absolutely the same. Both buzzed. The filter stopped one, not the other. The mute stopped it, but had no effect on the other.

Any ideas gladly received

 

[Raymo]

The filter helped clean up some noise that was being introduced somewhere in the electrical feed into the intercom (assuming that is where it was installed). You may have additional noise being introduced on plane #2 that needs additional filters. In the old days of plugs without resistors, we'd install a simple automotive ignition capacitor in the power line of the radio to clean up noise coming from the ignition system.

In general, when possible, it is best to find the source of the noise solve that problem.

It may help to review your grounding structure/connectivity and separate the audio grounds from the other A/C grounds, as much as possible. Then run one ground between the audio grounds and the battery.

 

[mike_newall]

Final closure - I was at Sun n Fun and visited the PS stand and asked them about the buzzing, the fix and the mute.

I explained it was a standard install as per instructions and almost immediately he said it is most likely coming from the music input as the mute button disables the music input. Probably caused by not isolating the socket from the structure, but the install was per instructions.

He then suggested plugging a phone or iPod into the socket and with mute off, see if the noise went away, it did, so it looks like it was caused by interference being generated by the music input socket.

Thanks to all who offered suggestions and thanks to PS Engineering for the explanation.