It was in standby at the time, not being used. I heard a loud clanking sound and went to find out what the noise was and then I smelt it.
I noticed when I first added the amp to my system it added a ground loop hum. I took care of it by running my coax to the cable box through an isolator but maybe I should have looked more into it at the time?
I could make use of another buttkicker anyway so I think I'm just going to buy the whole kit. I just hated spending the money to replace it(doing some new upgrades) but getting another buttkicker with it doesn't seem as bad. Makes me feel like at least I'm getting something out of it.