Soundblaster Live 5.1 Subwoofer out not working

hi, after two month without subwoofer, ( i thought the problem was the subwoofer), i figured out, that there is simply no output to the subwoofer. Anyone knows why? driver problem? card broken? i'm am using the first connector as center/subwoofer out and the center is working fine. the cabel is working, i tried two different ones, working at the rear output, and with both no sub output