According to the fault as a judge should be driving circuit fault, such as SC, SU, SD board, testing on SC board each test point voltage, measure TPSC1 point voltage of negative pressure, normal should be about 70 v, detection TPVSCN 28 v voltage is normal, so the judge fault parts should be in IC6511 and peripheral circuit, measuring IC6511 1 foot 15 v power supply is normal, try to replace IC6511 after normal machine.XQEservice manual download site