故障现象:刚开机工作良好;半小时至一小时后,放像出现水平噪波带干扰,伴音变调;随后图像时常出现静止画面,伴音时有时无;最终自动关机,停止工作。冷却几十分钟,又能正常工作一段时间,尔后故障更加频繁出现。夏天较冬天提前出现毛病,天若很冷则不出现问题。分析与检修:该故障有一个特点,与温度有关。环境温度直接影响机器的工作状态,检查故障一定要从散热不良方面考虑。放像不良且影响伴音,必然与带速有关,应当涉及到主导轴电机的工作情况,检修时应从主导伺服着手。故障出现时观察机内运行情况,发现主导轴电机转速不均匀,时尔有停转现象出现;主导轴电机驱动板很热,上面的集成电路周围已烧得变黑黄色呈焦糊状,有烧油漆的味道。这说明问题是出在主导轴电机方面。首先,将机器底面朝上,拆下底盖,露出底面电路 Symptoms: just boot work well; half an hour to one hour later, there are horizontal noise level interference, sound changes; subsequent images often appear still images, sound sometimes no; the final automatic shutdown, stop working. Cooling for dozens of minutes, but also for a period of normal work, and later failures appear more frequently. Summer earlier than the winter problems, days if the cold is not a problem. Analysis and Overhaul: This fault has a characteristic that is temperature dependent. Ambient temperature directly affects the working status of the machine, check the fault must be considered from the cooling side. Poor playback and affect the sound, the inevitable and belt speed, should be related to the work of the main shaft motor, maintenance should start from the leading servo. When the fault appeared observing machine operating conditions and found that the capstan motor speed is not uniform, there are occasional stall phenomenon occurs; capstan motor drive board is very hot, the above integrated circuit has been burned dark yellow was scorched paste, with Burn the smell of paint This shows that the problem is in the lead-axis motor. First, the bottom of the machine facing up, remove the bottom cover, exposing the bottom circuit