论文部分内容阅读
故障现象:电源指示灯亮,屏幕无显示,不能正常工作。检修方法:接通电源,绿色电源指示灯亮,显示屏无显示,电源开关不能控制电源通断,面板各功能按键均失效、整机不工作。据此初步分析故障出在电源或微处理器电路。测量开关电源各组输出电压+18V、5V、+12V 均正常,说明故障不在电源部分。由于该机显示屏是由微处理器 ICA2直接驱动,测微处理器 ICA2①、②、(28)脚(+5V 电源输入脚)电压正常;进一步测 ICA2各脚电压如下表中实测电压:(笔者用500型万表测量,并将 ICA2正常工作时所测电压做参考电压列入表1,以便同行修理时参考)把实测电压与正常工作时的参考电压进行对比,发现 ICA2⑩、(11)、(12)、(13)脚的电压
Symptom: power indicator light, the screen no display, can not work properly. Maintenance methods: turn on the power, the green power indicator light, the display no display, the power switch can not control the power off, the panel function keys are invalid, the machine does not work. Based on this preliminary analysis of the fault lies in the power supply or microprocessor circuit. Measurement of switching power supply output voltage of each group +18 V, 5V, +12 V are normal, indicating that the fault is not part of the power supply. As the machine screen is directly driven by the microprocessor ICA2, microprocessor ICA2 ①, ②, (28) feet (+5 V power input pin) voltage is normal; further test ICA2 voltage of the feet in the following table measured voltage: With the 500-type universal metrology measurement, and ICA2 normal work measured voltage reference voltage is listed in Table 1, so that when the same line repair reference) The measured voltage and normal working reference voltage comparison and found ICA2⑩, (11), (12), (13) the voltage of the foot