故障现象:光栅稍暗,无回波信号分析检查:首先调节面板上的“辉度”,”对比度”及“增益”调节纽,故障现象无改善。经观察,该机付机有回波信号,且亮度正常,从而排除了探头故障的可能性。打开机盖,未发现断线及接触不良的现象。用万用表测供电电源,正负供电正常。用接插板将二“发射与STC”板升高,用示波 Symptom: The grating is slightly darker, no echo signal analysis checks: first adjust the “brightness” on the panel, “contrast” and “gain” adjustment buttons, the failure phenomenon is not improved. Observed, the machine has an echo signal, and the brightness is normal, thus eliminating the possibility of probe failure. The lid was opened and no disconnection or poor contact was observed. Use a multimeter to measure the power supply. The positive and negative power supply is normal. Using a patch panel to raise the two “emission and STC” boards, using oscilloscopes