A few weeks ago, the control unit lost power while playing music and wouldn't turn on. No lights, no sounds. It's only been used as speakers to the TV or phones in the 5 years I've had it. Brought it to a service center and they said the issue is with the motherboard with a bill that's hard to justify.
Should I take it back and try to diagnose it myself? I've tried replacing the power cord because that's the extent of my abilities. The speakers work fine. I don't know about the other features because I don't use them.
You definitely don't want to invest any money in the control unit. If the service center was honest then there won't be anything you can fix in it.
If you wanted to use the tower speakers and center channel you would need a AV receiver that can handle 4 ohm speakers. Don't worry about the power specifications as they pretty much make those up in HTS package systems. Anything from 50-100 watts per channel should be fine. You won't be able to use the woofer because AV receivers all assume that you will have a self powered woofer. They have no way to know how much power the subwoofer you get needs so they just leave that amp out of the receiver.