[Xperia Z3 Compact Q&A, Help & Troubleshooting] TJCacher:
Hi - I am replying a bit late because I just came across this thread while trying to troubleshoot a problem I experienced with the FM Radio this evening, which until now has been functioning perfectly.

This may not be your problem, but I'm going to describe it and a work-around for it, in case others may find this thread later when searching for problems with the Z3/Z3 Compact FM Radio. I hope it helps you, as well.

The problem is apparently due to an unfortunate conflict between the FM Radio app and the Google Now voice-activated search settings ("Ok Google").

The main symptom of the problem is that the FM Radio will not play audio through either the headphones or the speakers. This may be misdiagnosed as a broken radio, or failure to tune any stations, but in reality the radio itself is functioning and stations are being tuned. There is just no sound coming from the speakers or headphones (regardless of the setting of the Headphone/Speaker switch within the FM Radio app).

I discovered the explanation for this problem at the following thread, which deals with the Sony Z2 model, and is claimed, on the thread, to only happen when the Google Experience Launcher (GEL) is used in lieu of Sony's stock launcher. Unfortunately, on my Z3 Compact, the problem is occurring despite the fact that I'm using the stock Sony launcher.

Here is a link to the thread:

http://www.thedroidbot.com/sony-xperia-z2-fm-radio-issue-google-now-launcher-fixed/

Basically, the problem is a conflict between the Google Now service's "Ok Google" voice detection and the FM Radio app. Disabling the service's voice-activation (being able to say "OK Google" to invoke the service in listening mode for verbally stating a query) will restore the FM Radio app's ability to play sound correctly.

To test if this is your problem, try the following steps (the FM Radio app should *not* be active while you do this - use the "Close All" item on the task switcher to make sure the app is not active if you have had it running):

1) Invoke the "Search & Now" settings for Google Services using one of these two methods:

a) Slide up and right from the "Home" icon on the device's bottom center to invoke the Google Now search screen, scroll to the bottom, and tap the "..." menu, and select "Settings"

-or-

b) Run the "Google Settings" app from the installed apps menu screens (or a shortcut, if you have placed one somewhere), and tap the "Search & Now" item

2) Select the "Voice" item

3) Tap the '"Ok Google" Detection' item

4) Uncheck any checked items on this screen ("From Google Search app", "From any screen", "From lock screen")

5) Tap the "<" back symbol at the upper left of this screen

6) Slide the "Audio History" switch to the Off position

7) Tap the "<" back symbol at the upper left of this screen

8) Tap the "<" back symbol at the upper left one last time to exit the settings app

9) Test the "FM Radio" app to see if it is now functional - if so, you must either choose between being able to use the FM Radio app or having the ability to invoke the Google Now service by using the "Ok Google" voice phrase (or you must memorize this sequence of steps and repeat them each time you wish to use the FM Radio app, and then re-enable them when you are done with the app).

NOTE: Disabling the voice activation feature of the Google Now service does *not* mean you are giving up the ability to do voice queries within the Google Now service. To do voice queries will simply require you to press the small microphone icon within the service or on the Google Search widget on your device's home screen to activate and place the service into listening mode.