G3X audio suddenly scratchy

[Ed_Wischmeyer]

Last flight, everything was perfect.

Today's flight, the comm radio was perfect, but the audio alerts from the G3X were weak and scratchy.

I'm thinking a loose wire, hopefully at the G3X end that's easy to get to. If it's at the audio panel end, that means taking the stack apart to get at the connector.

Thoughts? Comments? Am I missing something?

Glad Murhpy's Law is showing up two weeks before departure instead of day before...

 

[D-Dubya]

I'm not an electronics expert, and maybe one of those guys or a G3Xpert will chime in. But before taking the stack apart, maybe you can try something easier...

Do you have the schematic that says what those pin call-outs are on both ends? If you do, you can simply slide the audio panel out of the stack (should be just the one screw holding it in) and run continuity checks between the D-sub at the G3X PFD/MFD and the audio panel D-sub pins that are in the back of the stack. You'll need good eyes and a flashlight to read the numbers, but it can be done. Wiggle the harness around and see if the ohm reading varies. That may help pinpoint if it's just a loose wire or connection coming apart, and on which connector.

Check the grounds & shielding, too. It doesn't always make sense, but weak grounds can cause all kinds of gremlins.

 

[Ed_Wischmeyer]

run continuity checks between the D-sub at the G3X PFD/MFD and the audio panel D-sub pins that are in the back of the stack.

The D-sub at the audio panel is inaccessible unless the stack is taken apart. Bad installation by the "professional" shop that did it.

Thanks, though...

 

[Brantel]

The D-sub at the audio panel is inaccessible unless the stack is taken apart. Bad installation by the "professional" shop that did it.

Thanks, though...

You can remove the audio panel and probe the pins in the back. By the way, almost all the pro shops build their center stacks like that.

 

[Ed_Wischmeyer]

thanks, I can try that. But would a loose / intermittent show up on a continuity check with a VOM?

 

[BobTurner]

thanks, I can try that. But would a loose / intermittent show up on a continuity check with a VOM?

Murphy’s law says ‘no’. As soon as you look the problem will go away. But, sometimes you get lucky. Troubleshooting rule #1: Always test the easy stuff first.
Along the same line of thought: Pull the audio panel, spray the pins on the back and those inside the rack with contact cleaner, re-install. Most likely won’t fix it, but it’s easy to do.

 

[Ed_Wischmeyer]

The plan was to swap screens, left and right, and see if the problem went away.

Garmin tech support recommended saving my G3X settings first -- but the secret is that you have to hit the menu button once you're on the correct screen to do that -- and they also told me that in configuration mode, there is a Sounds button. I tried that, and all the alerts were undistorted, but maybe softer than expected.

So... no fault found. Hope it stays that way!

 

[N49ex]

If the problem persists, in addition to open/partially open connections, check for shorts for partial shorts on audio leads to ground. Opens are most likely to result in low or missing audio, shorts are more likely for scratchy or distorted sound, as the short or low impedance to ground presents an excessive load to the signal source. Also, when probing at connectors in the back of the housing, it's convenient to make some jumpers with the appropriate pin or female connector pin type to insert into the backshell connector. Much easier than trying to probe with a meter probe, less likely to bend or short a pin.

 

[Ed_Wischmeyer]

I think I found the problem (s).

1. Was using a Y connector to feed a GoPro. That connector paralleled an intermittently scratchy headphone connection.

2. In order to get enough intercom volume to the GoPro, the GMA245 intercom levels were high and the headphone sliders were low. The aural alerts from the G3X are fixed volume in the GMA245 and do not follow intercom levels. Thus, low slider settings stifled the G3X alerts.

I think.

We’ll see what Garmin has to say.

Ed