Phil Jones Briefcase Trouble

Hey all,

I've had this Phil Jones briefcase for about half a year now, and it's been perfect until now: when i turn it on and play its fine for about 5 minutes, but then the speakers make this strange static noise that gets really loud sometimes. I've even took out the input jack and it still makes the noise with nothing plugged into it, so it's definitely something wrong with the amp itself. It's always fine for a little while and then all of a sudden this weird popping and cracking noise starts happening, and sometimes it subsides after a while. It sucks...

Anyone have a similar experience? should I just send it in for repair??

Matt