I am building a mediacenter computer with an Antec OvertureII case and Asrock 775Twins-HDTV mobo, but my surprise comes when i push the power on button, and nothing comes out. After a couple of tests, i realized that the problem is caused by the Antec psu,( with other psu the mobo starts ok, and this psu works ok with other mobo ,so.... I think that the motherboard checks the -5V signal, but the SP450 ATX v2.0 Antec PS does not have that voltage(there is only 19 pin in the 20 atx connector). Any ideas?. Thanks!.