Loud Buzz in intercom from EMIS Alarm Pot

[N178EZ]

I have an intermittent bug where I get a very loud buzz/tone in the headset under some conditions. I seems to be higher power settings (higher buss volts while charging?). It will go away if I turn the alarm tone pot down far enough. Unfortunately that also mutes the alarm tones. It is tied into a PM3000 intercom aux input. I am a bit baffled because it works flawlessly 50% of the time (EMS alarms work, etc.) The buzz is different from the standard alarm tones that sound for say low oil pressure, etc. There isn't another tone for another warning that I am missing somehow is there?

 

[dynonsupport]

What product is this?

The EMS has only one tone, but the EFIS has two (altitude alerter and AOA). If you have a D180 they may be coming from the EFIS side.

 

[N178EZ]

I have an EFIS D10A and EMIS D10. I also think the software version I currently have loaded was prior to EFIS tones, but I am not sure. On the first flight the tone started just after liftoff and stayed through 5K ft where it was turned off via the volume pot.

 

[dynonsupport]

That sounds like it might be the EFIS AOA tone. That's been there for a few years now, so you'd have pretty old firmware to not have it.

Go into the setup menu and the AOAALM menu and make sure the AOA alarm is off.

If you have the AOA probe and want the alarms, you might need to turn it off until you can get the AOA calibrated.

 

[N178EZ]

Don't have an AOA probe installed, but I will check to see if that alarm is set.
Matt

 

[N178EZ]

First flight went great and after checking it appeared the alarm was in fact set (even though I didn't have a probe). Thanks as always for the timely help. You guys are awesome.