According to the phenomenon analysis, problem could be out in the power supply and CPU control circuit. Open the machine cover, use multimeter measuring PS3201 (13), (15) feet 3.3 V voltage is normal, measuring PS3201 (11) foot (+ 5 V) voltage is only 4.2 V, measuring the power plate connector PS1101 for + 5 V, 5 feet (11) foot (+ 5 V) voltage is 4.2 V, test the other voltage are normal, explain photoelectric coupler is normal, + 5 V voltage power supply branch only a fault or we should load. To test the power plate + 5 V voltage, found that only 3.5 V, measuring Qllll (S) voltage of 5.2 V, (G) voltage of 4.5 V, judged Qllll internal damage. After replacing Qllll, machine work 怍 returned to normal, fault line of chuhe.yreservice manual download site