I was at rehersal using my ampeg svt 4pro and after about 45 minutes it just shut off. After letting it sit for about a minute or two I tried turnig back on and then it was working fine. It would do this very so often. This is a rack mounted head. My question is if its getting too hot and because of insuficiant are flow due to the fan being mounted on the side rather than the back. Has anybody had this problem before? I use this with an 810 cab with a fender precision with EMG pj pickups.