See http://www.avforums.com/forums/showthread.php?t=385965&highlight=E55+Self+Check and leslierushforth entry on http://www.avforums.com/forums/showthread.php?p=3496863
Mine had this problem and I bought the little component, soldered it in, and problem solved for about £20. Bear in mind the warnings on these websites about the level of expertise needed, and don't try it unless you are into that sort of thing.
Phil
July 2008