Remove the casing, and check the function keys PCB OPERATE switch on and off is good, the main circuit board with no exception, check on the key board and the main circuit board strip connection between found a tear, platooninsert left bending position measuring found {1} feet. With 30 after 0.2 mm enameled wire connected with insert boot, electricity power supply indicator, various function keys back to normal.YM8service manual download site