Vistron DB32c-BD 32

Question

I have just got my new TV. Installation was fine and all channels were found. However, there is a buzzing noise coming from the set, but no actual sound. It is not on mute and as I turn the volume up the buzzing gets noisier. The picture is excellent.The sound works when there is DVD playing?!An exchange has been sorted out, but they can only do that after Monday. Is there a serious problem or is there something I can do to fix it