西门子CT机维修实例解析

admin

                    

                    

                    
                    
                    <h1><strong><span>一、故障现象</span></strong></h1><h1><span>西门子</span><span>SOMATOM Spirit CT</span><span>机 正常开机后，机架启动过程中始终提示正在进行同步，机架电源不能启动，扫描系统启动失败。</span></h1><h1><strong><span>二、故障分析</span></strong></h1><h1><span>进入到</span><span>Service</span><span>程序，查看</span><span>Eventlog</span><span>，提示错 误代码为： </span><span>CT MAR-21control error MAR</span><span>，描述为可能有以下故障：</span><span>①D522DMS(DataMeasurementSystem)</span><span>板的电源电压有故障</span><span>;②DMS</span><span>单元有故障。</span></h1><h1><span>2.</span><span><span>打开机架，在未断开负载的情况下，测量</span>DMS<span>单元的</span><span>W515D522</span><span>板电源电压，测量</span><span>XP1</span><span>接口各插脚间的电压，其中</span><span>2</span><span>～</span><span>6</span><span>脚为</span><span>D522</span><span>板提供</span><span>VDD</span><span>电源，标称值为</span><span>6.3V</span><span>，实测</span><span>6.5V;4</span><span>～</span><span>8</span><span>脚为</span><span>D522</span><span>板提供</span><span>VA_POS</span><span>电源，标称值为</span><span>6.05V</span><span>，实测</span><span>6.26V;5</span><span>～</span><span>9</span><span>脚为</span><span>D522</span><span>板提供</span><span>VA_NEG</span><span>电源，标称值为</span><span>6.05V</span><span>，实测为</span><span>6.25V</span><span>。上述工作电压均在正常范围以内。反复开关机，均无法启动机架电源，暂时未发现其他故障。</span></span></h1><h1><span>3.</span><span><span>停机半天后，重新开机，机架电源又能启动，</span> <span>且一切恢复正常，晚上正常</span> <span>关机。第二天早晨开机，</span>CT<span>机能正常启动，但图像间或出现环状伪影。第三天，环状伪影越来越重，作空气校准，能通过</span><span>;</span><span>作通道检测，提示</span><span>Module15mustbeexchanged</span><span>，描述</span><span>15</span><span>号</span><span>module</span><span>损坏。由于探测器模块</span><span>(module)</span><span>是固定在探测器上，不能单独更换，若是某组</span><span>module</span><span>损坏，只能连探测器一并整体更换。考虑到若是</span><span>module</span><span>后面的数据采集通道损坏，也会出现环状伪影，也可能出现相应的故障提示。检测各个具体的通道状态，提示</span><span>DMS</span><span>中</span><span>15 </span><span>号</span><span>slot</span><span>上对应的</span><span>225</span><span>、</span><span>230</span><span>、</span><span>231</span><span>等多个通道损坏。</span></span></h1><h1><strong><span>三、维修处理</span></strong></h1><h1><span>1.</span><span><span>西门子</span>Somatom Spirit<span>型</span><span>CT</span><span>机共有</span><span>3</span><span>块通道板</span><span>(DMS ConverterBoard)</span><span>，其中</span><span>15</span><span>号</span><span>slot</span><span>对应的是中间那块通道板</span><span>D524</span><span>。为进一步确定故障范围，可将通道板进行互换，观察故障现象是否有变化。互换时，先泄放掉手腕上的静电，并戴上防静电手套，将中间的通道板与右边的通道板进行互换，重作通道检测，此时提示</span><span>29</span><span>号</span><span>slot</span><span>损坏，故障位置发生了改变，证明中间的通道板损坏。</span></span></h1><h1><span>2.</span><span><span>订购一个同型号的通道板</span>(<span>电路板对应编号：</span><span>8715927)</span><span>，重做空气校正，再做一遍完整的质量检测，含水模检测、低密度检测、噪声检测等，均符合质量要求，</span><span>CT</span><span>机恢复正常。</span></span></h1><h1><span><strong><span>四、维修总结</span></strong></span></h1><h1><span>1.</span><span><span>该故障现象是一例通道板故障不断演变的过程。最初通道板出现故障，机架电源及扫描系统均不能启动，</span>CT<span>机诊断程序提示</span><span>DMS</span><span>电源可能出现问题</span><span>(</span><span>实际上</span><span>DMS</span><span>电源是正常的</span><span>)</span><span>。随着通道板性能进一步改变，机架电源及扫描系统又能启动，伴随着</span><span>CT</span><span>机图像开始出现伪影。此时运行诊断程序，提示探测器模块损坏</span><span>(</span><span>实际上探测器模块是好的</span><span>)</span><span>。进行具体的通道检测，软件又能检测出有故障的通道。</span></span></h1><h1><span>2.</span><span><span>大型医疗设备往往都配有功能较为齐全的故障诊断程序，我们可以充分利用软件的提示，缩小故障排查范围，但有时诊断软件提示的受损元件不一定准确，需要扩展思路，进一步确定故障部位，彻底解决问题。</span></span></h1><p><br  /></p>