From the failure phenomenon, no LCD screen is generally bad fluorescent display section, no filament voltage or external control voltage is not in place. Check the CON01 has AC220V input, control transformer secondary voltage AC 2.4V filament normal, while the measured voltage anode voltage are negative, indicating that there is no input drive level, the circuit IC1 (HD40316B38S) {21} feet with +5 V voltage, {8 }, {9} foot clock oscillation voltages are 2.8V, 2.1V, also normal, indicating a fault in the circuit between the drive circuit and the CPU, if only the driver circuit failure will only display a stroke segment abnormalities . Focuses on the investigation voltage IC1 {22} feet and IC2 {4} feet, circuit IC2 (SWM002) in CPU periphery, where {4}, {7} ~ {12} feet under CPU control, investigation IC2 {4} feet without after the input voltage (normally the terminal voltage should be 3.5V), found that when the investigation is connected with IC1 {22} feet of the pin Weld, repair welding handle its normal voltage, troubleshooting.nX4service manual download site