Ever since I got a Tivo box (Cisco) its made an annoying rumbling sound thats audible above the sound of the tv. An engineer has tried replacing the box (with another Cisco) but its made no difference. Ive also tried attaching foam feet to the box but this also made no difference. I have another engineer visit booked - please could they bring a Samsung box with them to try? The sound is starting to drive me mad!