This is a new 46

This is a new 46'' Sanyo Plasma TV DP46849 that was exchanged at Walmart in Jasper, AL on 9/28/09---we bought the original TV 46'' Plasma Sanyo DP42848 on 9/28/08 that had a picture problem---we do have an extended warranty--we are now having problem with the audio cutting in and out on current TV--this can happen at any time TV is on--it is now almost every other word that is missed and does have long segments where there is no sound at all---reminds me of a loose connection---can you help??