Inspection found a white dirt, circuit boards and key contact with anhydrous ethanol net dry cleaning, cover rubber, with a multimeter to measure voltage on both ends of the infrared transmitting tube, press the button, pointer only tiny wobble, normal should be 0.1 ~ 0.3 V voltage change. Scan button conductive rubber aging obviously, according to the size of the conductive rubber cutting circular repair adhesive aluminium foil, packed commissioning troubleshooting.6kjservice manual download site