I changed the batteries but had only 1.2 watts and had the same problem. I now buy a more alkaline watts. I did the reset and now it seems that everything is fine. it seems that the problem was in the power of the batteries. thank you all for your attention
Most use the pinpoint mode on the detector to roughly locate the target (plus most will tell you the approximate depth as well), then they use a hand held electronic pinpointer to zero in on the exact spot, allowing accurate excavation of the target without having to dig a massive hole. The hand held pinpointer saves a lot of time and frustration, especially trying to locate small metal targets, whilst also helping to minimise damage to both the coin/relic and grassed areas.