I have had my tx-p42g20b for about a week now and i notice a buzzing noise when the set is first turned on. It seems to be coming from the bottom right hand corner and lasts for about 10 - 15 mins then seems to fade. it seems to be louder as when the picture is brighter. is this just the tv warming up or is this the start of somthing bigger. What should i do return the set while it is still within its 28 days or is this normal. any advice welcome cheers.