Hello everyone, newbie here. I picked up a bose acoustimass 10 iv subwoofer from a friend. Had a blown fuse so I replaced it . Has power now but all I'm getting out of it is humming. Took the boards all out and visually everything looks good but unsure how to test all the power outs from transformer. I heard the unit won't work without the bose system to power it but seen videos of it working with a Sony Amp aswell as denon and onkio. It's a nice sub and would love to hook it to my Harman Kardon