My Discover Pro Nav system has lost all sound. No sound from radio, CD, media, nav, phone, touchscreen notifications.

I switched the radio on one day and no sound. However it sometimes comes "back to life" and then no sound again.

I have tried resets and disconnected the battery for 10 mins with no success.

I have heard that this is a known fault and the fix is to replace the output amplifier.

Has anyone else had the same problem and managed to get it fixed??