故障现象：按充电按钮不能充电，按放电按钮未有放电动作。分析检修：在充电电路中，由振荡电路产生高频振荡经变压器和整流电路给电容充电。按下充电按钮，未听见高频振荡声，说明振荡电路未产生振荡。先从外围电路检查，很快查到故障出在按钮开关上。但此种开关在市场上很难 Fault phenomenon: Press the charge button can not charge, press the discharge button has no discharge action. Analysis and maintenance: In the charging circuit, high-frequency oscillations are generated by the oscillation circuit and the capacitor is charged by the transformer and the rectifier circuit. When the charge button is pressed, no high-frequency oscillation sound is heard, indicating that the oscillation circuit does not oscillate. First check the peripheral circuit and quickly find the fault on the button switch. But such switches are difficult in the market