For those who are facing the Silent issue and unable to wait till Mighty next announcement for 4.9 or 5.0, here is one alternative to get rid of this ringer problem.
Copy your ring tone from \Windows\Rings to your PC
use any wma to wav converter (eg.
http://www.4musics.com/wma-to-wav.exe) and convert it to .wav file (like -> Alert-Sonar.wma to Alert-Sonar1.wav)
Now copy this converted file to same folder in Diamond (\Windows\Rings)
Go to Settings\Sounds & Notifications then under the Notification change your Ring tone to converted ring tone.
While my phone got silent, I've not done a soft-reset and tried it to prove this exercise and I found when I'm selecting converted file in Ring Tone, my phone is ringing properly and if I'm going back to original ring tone file (.wma) it was not ringing during incoming call.
Trust it will help few users who have not google all the posts and repeating same issue again n again
s@n