ＸＤＨ－３Ｂ心电图机描笔单偏故障检修一例故障现象机器开机后，观察开关置＂准备＂档，描笔单偏；置＂观察＂档，仍单偏且无法调至中心。分析检修根据故障现象断定故障可能与放大系统和位置反馈系统有关。为判断故障究竟在哪一系统，笔者设想断开反馈系统与放大系统的连... XDH-3B electrocardiograph trace pen single bias troubleshooting an example of the phenomenon of failure After the machine is turned on, observe the switch set “ready” file, trace pen single bias; set “observation” file, still single and can not be transferred to the center. Analytical maintenance It is concluded that the fault may be related to the amplification system and the position feedback system according to the fault phenomenon. In order to determine which system the fault is on, I envisage disconnecting the feedback system from the amplification system...