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故障现象1:开机后屏幕显示内存奇偶校验错,死机。 故障分析及维修:这类故障可能是RAM部分的奇偶校验错,也可能是奇偶校验电路有问题。由电路图可知,出现RAM奇偶校验错,经过U27、U14、U13后,最终在U55的第9脚产生一个低电平的PAR信号,表明产生了奇偶校验错。PAR信号送至82C201芯片的第24脚,经内部判别在第18脚上输出PCHK信号去请求NMI中断。 检测U55的第9脚PAR信号为高电平,可82C201芯片的第18脚却输出的是高电平,显然是82C201芯片损坏。更换后,故障排除。 故障现象2:开机后屏幕无显示,运行灯也不亮。 故障分析及维修:先检查电源电压、PG信号及
Symptom 1: After the boot screen memory parity error, crash. Failure Analysis and Maintenance: Such failures may be part of the parity of RAM errors, it may be a problem with the parity circuit. As can be seen from the circuit diagram, there is RAM parity error, after U27, U14, U13, the final in the U55 9 feet to produce a low PAR signal, indicating that parity error has occurred. PAR signal sent to the first 24 feet of the 82C201 chip, the internal judge in the first 18 feet PCHK signal output to request NMI interrupt. Detection of the 9th pin U55 PAR signal is high, the first 18 feet 82C201 chip output is high, apparently 82C201 chip damage. After replacement, troubleshooting. Symptom 2: no display after boot, running lights are not bright. Failure Analysis and Maintenance: First check the power supply voltage, PG signal and