I have a powered JBL subwoofer that's part of my home theater setup. Recently, however, it's been making machine gun noises when turned on.

I can let it blast a few times (10 to 15 times) until it stops, and then it works fine for like 20 minutes but automatically shuts off when it's had enough.

I've only done that twice, and am afraid to use it and ruin it now.

Does anyone know why it's doing that, or what I can do?