故障现象分析:打开主电源开关,测+115V正常,按关机键无伴声。再按二次开机键机器正常工作,此故障表明开机/待机控制电路有故障。故障检修过程:待机时测Q830(b)极电压有5V,说明CPU开机/待机控制电路正常,故障可能在Q830、R847、Z801测Z801的(9)脚电压为0.6V与正常待机电压相同,测Z801(3)脚电压为2.4V,与正常时待机电压为4.8V,开机电压为2.4V,说明Z801有故障。更换Z801机器开机正常。 |
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