I got the same story, have you gotten anywhere further with them on your set
Samsung Customer Service is telling me that this is one model (HLT6756WX/XAA) that their "engineers" have determined does not have a problem. It sure seems to me that that there are a number of sets out there with this problem as people are posting it here and on other boards. Unfortunately, Samsung does not seem to be willing to step up to the plate and guarantee customer satisfaction for a known problem. I tried to speak to a supervisor but one wasn't available and is supposed to be calling me back within 24 hours.
This is not the Customer Service I would expect from a world class company.