I received my Xcal back from repair and still have a problem. If you wave your hand pass the body of the machine ,it sounds off ,as if you waved it passed a coin. This will happen in all modes.This has never happened in the past. I have used this machine for Three years..If i pass the coil over a metal object it has a low pitch crackle and then dead silence. As if it was overloaded. I have tried lowering the sensitivity down but it did not help.There are times it will work fine, but most of the time it will not. They have replaced the board with a new one , but i still have a problem.I have read this has happened too someone else about a year ago but cannot locate the article.I believe it had to do with a build up of static. But don't remember the solution.Any ideas before i send it back.Tk's