Ok, well here about maybe two months ago, give or take, I bought a Crate GFX 1200H guitar amp head from a friend for about $80. His band had used it quite often for their shows. They never had any problems with it and it's not that old. Well I've used it for these passed two months and have had no problem. Well my band is playing some pretty hard metal so of course I'm playing with a lot of gain. Well here recently I can't play over 2 gain without it letting out a horrible screech.. I've checked all of my connections, highs, lows, and mids, etc. and nothing has been messed with. I've tried different cables and all that good stuff as well.. as well as another guitar. I'm assuming the head is going pretty bad, but I figured I'd get a few opinions first. If so, atleast I only paid 80 bucks for it..

Thanks in advance!