This is an often-reported problem, usually fixed by replacing a capacitor in the power supply. You can start at http://www.tivocommunity.com/tivo-vb/showthread.php?p=7410869#post7410869
You can swap the cables and see if the problem follows the cable - but it probably doesn't.
You can swap the cables and see if the problem follows the cable - but it probably doesn't.