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  #21  
Old 03-26-2015, 10:19 AM
664781 664781 is offline
 
Join Date: Jan 2005
Location: Powder Springs, Ga
Posts: 261
Default Side Tone

I had a very similar problem and fixed it with the SL40 settings. Van's presets did not work on mine for some reason.

Stein got me going in the right direction.
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  #22  
Old 03-29-2015, 06:47 PM
rgmwa rgmwa is offline
 
Join Date: Feb 2010
Location: Perth, Western Australia
Posts: 1,498
Default Headset noise

Further to my previous post about the repetitive buzz/click noise I was experiencing in the headsets, I put a post on Dynon's forum. Jake (Dynon Australia) promptly responded by PM and phone to help troubleshoot the problem. He even rang me on a Saturday evening at 10:30 pm (his time) - fantastic service! Anyway, after some experimenting (eg. engine on/engine off, different headsets, disconnecting the EMS etc) to try to isolate the source of the problem, I found that the noise finally stopped when I disconnected the backup battery. I re-connected it to confirm that the battery was causing the problem. To my surprise - no more noise. Connected everything back up, powered up the system several times, flipped all the switches etc and everything works fine. Don't know what the problem was - maybe something to do with micro-Molex connector. The other issue of the SL40 feedback was easily fixed by Joe's suggestion, so all is well again.
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  #23  
Old 06-28-2015, 07:37 AM
rgmwa rgmwa is offline
 
Join Date: Feb 2010
Location: Perth, Western Australia
Posts: 1,498
Default Fixed now...

I spoke too soon in the previous post. While Dynon's support has been excellent, the problem turned out not to be a fault in the Skyview.

To go back about three months, I've had a constant `bzzt....bzzt...bzzt' sound in my headset repeated at exactly one second intervals. Both pilot and co-pilot sides were affected. The sound level stayed constant despite adjusting the intercom squelch and volume knobs, and was unaffected by the transponder, radio, autopilot or lights. At first I thought the sounds were related to the flashing warning signs on the Dynon, but later realised they were exactly timed to the digital clock on the display. The noise would start as soon as the boot sequence got to `starting network manager'. If I unplugged the GPS antenna from the AV5000 module so that the system couldn't pick up the time signal from the satellites, the clock would not appear and neither would the noise. Dynon initially thought it might be related to the transponder, but neither disconnecting the transponder, the EMS, or anything else seemed to make any difference. If the clock was active, so was the noise. The only way to get rid of it was to disconnect the GPS antenna, which wasn't really a good solution. However, flying with the noise wasn't an option either as it was as irritating as a dripping tap.

However, I got lucky this afternoon when a local electronics guru happened to be at the field. He spent a couple of hours trouble-shooting the system, checking the Skyview settings, the radio, tracing the wiring diagram, pulling pins, etc, until he eventually discovered that the noise was apparently being generated by interference between the music jack wires and the tunnel harness, which runs to the ADAHRS mounted in the tail cone. When the GPS antenna was connected, it appears that EMF generated in the network cable was being fed into the audio wires that run close to the cable in the tunnel, and was therefore audible in the headsets. Disconnecting the two audio wires fixed the problem. It was a simple solution, but tracking down the cause has been a very frustrating exercise. Glad it's been fixed now.
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  #24  
Old 06-28-2015, 04:41 PM
dinowal dinowal is offline
 
Join Date: Dec 2011
Location: TWIN WATERS, Queensland, AUSTRALIA
Posts: 78
Default Valuable info

Hi Robert, - That's an important post, - for me any way! My aircraft has EXACTLY the same symptoms as you described so well. I had figured out that the regular pulsing noise & hash was coming from the Skyview, as it went away when the SV was turned off, but I had no idea where it was getting in to the audio system. Can you please advise exactly where & how you disconnected (cut?) the music input wires?
I had not planned to ever use the music input anyway,so no loss there, I suspect when I get my aircraft flying,(soon), there will be quite enough inputs of various types to fill my brain without music as well! Thanks very much, DEAN
PS Congratulations on your recent first flight!!
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  #25  
Old 06-28-2015, 05:34 PM
mturnerb mturnerb is offline
 
Join Date: Apr 2015
Location: Ponte Vedra, FL
Posts: 336
Default

I had a somewhat similar noise issue with my Garmin GTR-200 as intercom (not sure what you're using). I ended up (at Van's suggestion - thanks to Rian) simply turning down the audio input volume level - took care of the problem. Apparently the audio input is low-impedance and very sensitive to noise from external sources (in my example thought to be strobe lights and alternator - one noise source pulsed with the strobes and the other "whining" noise varied with engine RPM).
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  #26  
Old 06-28-2015, 06:23 PM
rgmwa rgmwa is offline
 
Join Date: Feb 2010
Location: Perth, Western Australia
Posts: 1,498
Default

Turner, mine is the Garmin SL-40/Flightcom 403 combination. Dean, we pulled pins 2 and 20 from the tunnel connector where it plugs into the AV5000 (but check your wiring diagram to be sure). It was a long afternoon, and it was getting dark when we finally worked out what the problem was. I think it has also cleaned up the other minor Skyview hum and other little extraneous background noises that I was hearing before, but that weren't really a problem. The really annoying sound was the clock pulse. I'm at work again today so will have to wait for the weekend to check thoroughly. The music jack wires should be shielded according to the electronics guy. I haven't had time yet to see whether they are or not, but I'm not too bothered as I wasn't planning to use the jack anyway.

It's nice to finally have the plane in the air. My test pilot, who normally flies a PC12, said it's `a great aircraft and flies beautifully'. Hope your test flight goes well.
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Last edited by rgmwa : 06-28-2015 at 06:25 PM.
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  #27  
Old 06-28-2015, 11:13 PM
jakej jakej is offline
 
Join Date: Aug 2005
Location: Adelaide, Australia
Posts: 49
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Great to hear it's 'fixed' Rob. One thing to consider is although you may have shielded wire on the audio IN jack it may not have the shield grounded at the Intercopm end which is a must for all audio

I trust the test flying will be a bit 'quieter' now :-)

Jake J
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  #28  
Old 06-28-2015, 11:36 PM
rgmwa rgmwa is offline
 
Join Date: Feb 2010
Location: Perth, Western Australia
Posts: 1,498
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Yes, thanks Jake. Fingers crossed. I hate electrical problems even more than fibreglass. At least I can see the fibreglass.
Cheers
Rob
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  #29  
Old 06-29-2015, 07:46 AM
Mich48041 Mich48041 is offline
 
Join Date: Apr 2008
Location: Riley TWP MI
Posts: 2,399
Default

I posted this issue on the AeroElectric List to get other opinions. The consensus is that the music jack, or any audio jack, should NOT be grounded to the airframe. The music jack should be insulated from the airframe with a dedicated ground wire going back to the intercom. Any signal that gets amplified is especially vulnerable to noise. Audio circuits should NOT share current paths (ground) with other aircraft circuits. Sets of wires that are twisted are less vulnerable to noise than parallel wires. For those who do not want to disconnect the music input circuit, I suggest that the jack be insulated from ground and that the 3 wires (ground, left, & right) be twisted together.
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  #30  
Old 06-29-2015, 10:29 PM
jakej jakej is offline
 
Join Date: Aug 2005
Location: Adelaide, Australia
Posts: 49
Default

Quote:
Originally Posted by jakej View Post
Great to hear it's 'fixed' Rob. One thing to consider is although you may have shielded wire on the audio IN jack it may not have the shield grounded at the Intercopm end which is a must for all audio

I trust the test flying will be a bit 'quieter' now :-)

Jake J
Joe - just wanted to make my statement clearer. All audio shielded wiring should be grounded at the Intercom ground bus (on the Intercom itself)
Just follow the manuals & particularly the PS-Engineering ones &- they are the best GA audio people IMO

Jake J
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