According to the fault phenomena analysis, the power indicator light is not bright, dc abnormal. Measuring output rectifier bridge pile, but the pressure drop fluctuation is bigger. Shutdown, switch tube is normal under the static test, all normal; Such displays general has over current or over voltage protection device, when the line scan circuit output abnormal, the measured voltage + 110 v, thereby to judge the line scan circuit "overload" phenomenon; The multimeter test line output circuit, the measured damping diode has been found breakdown, forming pathways. After replacement, troubleshooting.v3mservice manual download site