Last year when I first got my 4000 I had problems with the protect circuit/light coming on...making the amp go on and off for about a minute or so. It was sitting next to a Tech 21 guitar stack and when it was moved away from it it stopped...until now. The other night at my very first audition for a band, after about an hour of playing...it happened again. this time the stack was sitting next to a Peavey Bandit 112 and a Bheringer 412 cab. Fortunately I allready had done enough playing to get the gig with them. But now they are worried about problems occuring on stage...rightfully so. Has anyone had this problem. Anyone have a fix. At this point I don't have any extra cash to go get a new head so I have to stick with this one. Any help is greatly appreciated.