I've had my GTI 2500 for almost a year, and about a month ago it started acting weird when I try to pinpoint. As the coil passes over the target, there is an electronic clicking noise, then the detector goes silent over the target, then gets loud after passing the target. It's very much like the old bfo's that would null over rusty metal, except that this happens while pinpointing coins. I've tried the factory reset several times and the batteries are new. Sometimes it works perfectly, but the null is occurring more often now. I usually search in zero discriminate, but the same thing happens when pinpointing in coin, jewelry and custom modes. Sure hope somebody can give me some suggestions. Thanks. Jugg