The set could be working fine for hours but eventually it'll make a loud alarm type noise and you have to shut it off then turn it back on to get rid of the noise. This is the second vizio that I've seen does this. On the other vizio I put a small computer type fan on the main board and that did away with the noise. On this one it still happens though. I'm wondering if any of u guys have had the same problem? Thanx.