现就我院ＩＣＵ病区使用的有一台ＥＣＧ—6511心电图机出现的二例故障作一介绍。1　故障一在工作时有不走纸现象,时好时坏,后来竟不能工作。该心电图机由马达速度控制电路控制记录纸驱动马达转速,此电路马达为一永磁直流马达,用ＭＣ1406型集成锁相器构成锁相环电子稳速电路来稳 Now I will introduce one case of the failure of an ECG-6511 electrocardiograph used in the ICU ward in our hospital. 1 When the fault occurred, there was no paper movement during work. The ECG machine controls the rotation speed of the recording paper drive motor by a motor speed control circuit. The circuit motor is a permanent magnet DC motor, and an MC1406 type integrated phase locker constitutes a phase-locked loop electronic steady speed circuit for stability.