As I was preparing to head down to KSLE for the Garmin open house this afternoon, I noticed several issues relating to my GNS430 (the irony!) that caused me to cancel my trip. I just flew my airplane the other day, and fly it regularly. For reference, I have a GRT Sport EFIS, GNS430, GTX327 transponder, PS Engineering intercomm, and two MGL backup instruments.
First, roughly 30 seconds after turning the radio master switch on, a high-pitch tone would start increasing in volume, and persisted to the point where it was difficult to hear ATC over the radio, and my passenger over intercom. So, I went in to troubleshooting mode for this issue and found:
1) ATC could not hear the tone over the radio; comms over frequency were clear;
2) When first turning the radio master on, I could hear ATC clearly over the radio, and could clearly hear over the intercom with the tone not present at first;
3) It made no difference if the engine was on or off...the tone would still always return;
4) The tone seemed to start at around the time both the 430 and the MGL instruments are finishing booting up, though I haven't been able to definitely isolate it to either the 430 or one of the MGL instruments;
5) The headsets both seemed to be seated properly, and the headset jacks didn't seem loose. I heard no difference in the tone with messing with the headphone jacks, and the tone did not change when unplugging one headset or swapping headsets/jacks. The issue does not appear to be related to the intercom;
6) I don't have circuit breakers that can be pulled for some components like the MGL instruments, but I cycled power one at a time to the systems that I could and found no change in the tone. I was not able to cycle power to the 430 or the MGL instruments;
7) I crawled under the panel and looked for anything loose at the back of the 430 and found one wire lose. I tightened it but it made no impact on the tone;
8) Changing frequencies didn't change the tone at all;
9) Change in engine RPM didn't seem to change the tone. However, at times the tone would fade slightly and then get louder, but I couldn't correlate that to anything.
I also had the following two messages on the 430 that I'd never seen before: "G/S Needs Service", and "VLOC Needs Service".
I washed the airplane for the first time 24 hours prior, so I'm wondering if I maybe got something wet in the panel, or possibly did something to an antennae when I was cleaning? Or perhaps the timing of the washing and cleaning is coincidental?
Any thoughts or ideas out there on either the tone or the 430 messages? Thank you!