An electrical connector includes a housing having a mating face and a mounting face. The specific gravity of the artificial stone chips is the same as or similar to the specific gravity of the first resin matrix. The controller is programmed to include a series of games to be played on the apparatus that become progressively more difficult. Some locating elements are mechanically fixed to the chuck for securing the workpiece from transverse movement on the chuck surface. An expected value checking circuit 30 compares and checks this pattern data against the expected value pattern data and then outputs the diagnosis result regarding whether the logical circuit 18 is normal or abnormal. At least two of the LEDs in the circuit are capable of emitting different colored light with respect to each other.