Garmin 430 + Audio panel no sidetone
 

Any tips before I bend myself into a pretzel getting in, under and behind the instrument panel to troubleshoot the following:

Both left seat and right seat headset jacks not giving sidetone on COM1 (garmin 430). COM 2 (SL30) is fine so I assume the Garmin audio panel is not the problem. Got into the 430 programing set up and verified that sidetone is set for a high numerical value, so I don't think its software.

Anyone any ideas?

Give Brian at Home - Bournemouth Avionics a call - he will be able to help - and if not, fly in and he can fix it :)

Turn off the GMA340 audio panel. Com 1 will still work (fail-safe mode). See if you now have sidetone from the 430. If not, the GNS is faulty. We've had instances of early-build GMA340 audio panels causing this problem. It can't be wiring if the GNS receive audio is OK as receive audio and sidetone are on the same wires to the audio panel.

Was the GNS430 installed by certified personnel? If not, get one to look at it.

First check for me would also wigglyamps suggestion, turn off the audio panel and see the behavior in failsafe mode.

+1 on Brian from Bournemouth Avionics

Mochas gracias on the fail safe tip, still no sidetone, I guess my 430 is the knackered.