GTR 200 audio noise

[Dave12]

I fired up my 12 today for a flight and when I powered up the avionics, I noticed a whine in the radio audio. It appears to be alternator noise as it accelerates with rpm increase. I also hear the strobes flashing. I know we have filters on the fuel pump and a/p servos, but don't recall any in the charging circuit. Anyone else experience this? Mr. Gores, any advice?
Thanks in advance.

 

[mturnerb]

Try turning down the aux input volume available using menu button - looks like a music symbol. It is very sensitive to external noise. I had the same problem and this was the easy fix.

 

[BigJohn]

Hi Dave,

If the noise just suddenly appeared, I would have to scratch my head and try to remember anything that might have changed since the last flight. Unusual that the noise would just show up without a cause like that.

BTW, attended PCB at Piseco Airport yesterday, home of N588DF.

John

 

[Dave12]

Hi Dave,

If the noise just suddenly appeared, I would have to scratch my head and try to remember anything that might have changed since the last flight. Unusual that the noise would just show up without a cause like that.

BTW, attended PCB at Piseco Airport yesterday, home of N588DF.

John

I wish I had known of their event, I would have been there. I was already in Scranton in the morning. I am thinking a spike of some sort when I switched it on.

 

[Mich48041]

The only filter that I am aware of is the 22,000 microfarad capacitor inside of the switch and fuse module. And its effectiveness is debatable. I will not be much help here. Try Turner's suggestion.

 

[g3xpert]

I fired up my 12 today for a flight and when I powered up the avionics, I noticed a whine in the radio audio. It appears to be alternator noise as it accelerates with rpm increase. I also hear the strobes flashing. I know we have filters on the fuel pump and a/p servos, but don't recall any in the charging circuit. Anyone else experience this? Mr. Gores, any advice?
Thanks in advance.

Hello Dave,

We can probably help you better via email, but regardless, it will be important to gain a better understand of the meaning of "whine in the radio audio".

As you know, your GTR 200 provides intercom audio, COM radio audio (receive and sidetone), optional alert audio via the AUX 1 and/or AUX 2 mono audio inputs and optionally music audio via the stereo music input.

It will be important to understand which audio path(s) are picking up the noise.

For example, "radio audio" seems to imply that you are hearing alternator whine when receiving on the COM radio, but since this isn't mentioned specifically, perhaps you are referring to intercom, alert, or music audio.

Even if you can hear the alternator whine in the intercom audio, we wouldn't know if it is really just present in the intercom audio without removing the alert AUX 1/2 audio and music audio contributions.

To shut down the AUX 1/2 audio input path (probably only AUX 1 used on your RV-12), go into configuration mode and set the AUX 1 and AUX 2 volumes to 0%. Write down the old setting so you can restore it after making this test. If the alternator whine is now gone, we know that it is being coupled in on one of the AUX audio inputs.

Shutting down the music input is simple. Either turn the music input off (most of us have one of the two softkeys set to music on/off) or set the music volume to 0%.

As part of your noise input isolation testing, you might also unplug each of the headsets one at a time and see if that makes a difference.

Once you can provide some additional information on which audio stream the alternator whine is present, we might be able to suggest some mitigation.

Thanks,
Steve

 

[Dave12]

Hello Dave,

We can probably help you better via email, but regardless, it will be important to gain a better understand of the meaning of "whine in the radio audio".

As you know, your GTR 200 provides intercom audio, COM radio audio (receive and sidetone), optional alert audio via the AUX 1 and/or AUX 2 mono audio inputs and optionally music audio via the stereo music input.

It will be important to understand which audio path(s) are picking up the noise.

For example, "radio audio" seems to imply that you are hearing alternator whine when receiving on the COM radio, but since this isn't mentioned specifically, perhaps you are referring to intercom, alert, or music audio.

Even if you can hear the alternator whine in the intercom audio, we wouldn't know if it is really just present in the intercom audio without removing the alert AUX 1/2 audio and music audio contributions.

To shut down the AUX 1/2 audio input path (probably only AUX 1 used on your RV-12), go into configuration mode and set the AUX 1 and AUX 2 volumes to 0%. Write down the old setting so you can restore it after making this test. If the alternator whine is now gone, we know that it is being coupled in on one of the AUX audio inputs.

Shutting down the music input is simple. Either turn the music input off (most of us have one of the two softkeys set to music on/off) or set the music volume to 0%.

As part of your noise input isolation testing, you might also unplug each of the headsets one at a time and see if that makes a difference.

Once you can provide some additional information on which audio stream the alternator whine is present, we might be able to suggest some mitigation.

Thanks,
Steve

Thanks for your response Steve. To go a bit deeper with this, I have dialed all the inputs down from the menu and the noise still exists until I turn off the radio. My wife also brought to my attention that while flying, the screen on the radio appeared to have a light flashing intermittently which I assume is the backlighting. I took a short test flight today and noticed that the screen is going completely white and losing the info. on the screen. I was also reminded that we did smell a very slight electrical odor around the same time. I have contacted Lancaster Avionics regarding this and they have agreed to look at it Wednesday morning. What do you think?

 

[g3xpert]

Thanks for your response Steve. To go a bit deeper with this, I have dialed all the inputs down from the menu and the noise still exists until I turn off the radio. My wife also brought to my attention that while flying, the screen on the radio appeared to have a light flashing intermittently which I assume is the backlighting. I took a short test flight today and noticed that the screen is going completely white and losing the info. on the screen. I was also reminded that we did smell a very slight electrical odor around the same time. I have contacted Lancaster Avionics regarding this and they have agreed to look at it Wednesday morning. What do you think?

Hello Dave,

Certainly seems like you should be contacting Garmin customer support via the email or phone shown below.

Thanks,
Steve

 

[climberrn]

I could give my worthless internet opinion, but it looks like Garmin support is more than willing to help. Seems like a good place to start.

If you still want an opinion, let me know. I'll come up with something