Do you have a Garmin GTR 225A Radio installed in your Aircraft or one set up in a test rig on a Bench?
If so I would like to plug my Radio into your working installation in order to test it.
The fault on my Radio is an echoing feedback noise while transmitting on the ground so it is unlikely to cause any damage to your installation.
I am located in Southeast England but willing to travel a reasonable distance.
 
Thanks and regards,
 
Richard Shone (RV12)