Page 1 of Sony DAV S300 - Front right speaker sound problem - Help!!!

Recently my Sony DAV S300 has developed a problem whereby the sound level from the front right speaker suddenly drops really low 10-20 minutes into playing a DVD. I tried plugging one of the other speakers into the socket when this occurred once to see if it was a problem with the actual speaker or cable but the sound level remained low, so I guess it is a problem with the output socket at the back of the unit. The problem seems to rectify itself when the unit has been off for a few hours but only to occur again the next time I play a disc. Anyone have any ideas of what could be causing this and anything I could do (other than send the unit away for repair)?

Just a thought, but perhaps it is overheating? Is it tucked into a rack with other kit on top? Might be worth trying sitting it on it`s own with some space for air to circulate, and see if that makes a difference...