I have used the above model Audio/Video receiver for over 3 years until now, with no problem. In the last week it has lost all of the station and volume/bass/treble settings each time it's switched off. I've reset them 3 times, and left it in in standby mode for 3 nights, but as soon as it's switched off completely, all settings are lost. Is anyone aware of a reset, or an internal battery that may need changing ? Thanks.