This page will be expanded as time permits and is intended for our customers (you) to help in diagnosing radio problems so as to help us fix your plane quicker, or even help you fix the problem yourself. All information you can provide will reduce our time spent diagnosing the problem and reduce your end cost for the repair.
First are you operating it properly? I (Robbie) have done this so don't take it personal, the first thing I ask myself is what am I doing wrong? and many times it is something I have done. For instance if someone has used or worked on your plane last did they turn off the radio?
Are any breakers tripped? Check them all not just the one for the offending radio.
Check the audio (ADFs, NAVs, etc...) is it normal?
Are any of the other radios interfering with the problem radio? Try turning off other equipment (while listening to the audio), this would also include alternator, mags, etc...
More to come...............