西(xi)門(men)(men)子(zi)NCU維修(xiu)(xiu)必須(xu)在對西(xi)門(men)(men)子(zi)840D系統(tong)維護(hu)前，必須(xu)對NC以及PLC程序做好備(bei)份。在通電(dian)情況下，取(qu)出西(xi)門(men)(men)子(zi)NCU-BOX正面電(dian)池與風扇插卡，可(ke)用(yong)工業酒精清洗(xi)，然后用(yong)電(dian)吹(chui)風烘(hong)(hong)(hong)干(gan)。西(xi)門(men)(men)子(zi)NCU維修(xiu)(xiu)下面雙風扇，可(ke)以直(zhi)接(jie)取(qu)下，用(yong)酒精清洗(xi)，電(dian)吹(chui)風烘(hong)(hong)(hong)干(gan)。在斷電(dian)情況下，將(jiang)西(xi)門(men)(men)子(zi)NCU維修(xiu)(xiu)一起取(qu)下，NCU主板(ban)小(xiao)心取(qu)出，打開BOX蓋子(zi)，取(qu)出電(dian)源板(ban)，用(yong)酒精清洗(xi)，電(dian)吹(chui)風烘(hong)(hong)(hong)干(gan)。

西門子(zi)NCU維修的方法：1.電(dian)(dian)源接通后無(wu)基本畫面(mian)顯(xian)示(shi)，電(dian)(dian)路板(ban)(ban)(ban)03840號板(ban)(ban)(ban)上無(wu)監控(kong)(kong)燈顯(xian)示(shi)，電(dian)(dian)路板(ban)(ban)(ban)上監控(kong)(kong)燈亮，監控(kong)(kong)燈閃(shan)爍(shuo)，如果監控(kong)(kong)燈閃(shan)爍(shuo)頻(pin)率為(wei)1Hz，則EPROM有故(gu)障(zhang)；如果閃(shan)爍(shuo)頻(pin)率為(wei)2Hz，則PLC有故(gu)障(zhang)；如以4Hz頻(pin)率閃(shan)爍(shuo)，則保持電(dian)(dian)池報警(jing)，表示(shi)電(dian)(dian)壓(ya)已不足。監控(kong)(kong)燈左滅右亮。西門子(zi)NCU維修表示(shi)操作面(mian)板(ban)(ban)(ban)的接口板(ban)(ban)(ban)03731板(ban)(ban)(ban)有故(gu)障(zhang)或(huo)CRT有故(gu)障(zhang)。通常的原因有：CPU有故(gu)障(zhang)；EPROM有故(gu)障(zhang)；系統總線(xian)（即背板(ban)(ban)(ban)）有故(gu)障(zhang)、電(dian)(dian)路板(ban)(ban)(ban)上設(she)定有誤、機(ji)床數(shu)據錯(cuo)誤、以及電(dian)(dian)路板(ban)(ban)(ban)（如存儲器板(ban)(ban)(ban)、耦合(he)板(ban)(ban)(ban)、測量(liang)板(ban)(ban)(ban)）的硬件有故(gu)障(zhang)。

西(xi)門子(zi)NCU維修(xiu)由于電源(yuan)板或(huo)存儲曾(ceng)被拔出，從而(er)造(zao)成存儲區混亂。這是一種軟故障，只要(yao)將(jiang)CNC內(nei)部程序清除并重新輸入即可(ke)排除故障，電源(yuan)板或(huo)存儲器板上的(de)硬件(jian)故障造(zao)成程序顯示(shi)混亂。在(zai)自(zi)動(dong)方式下程序不能啟動(dong)，如(ru)此時產生351號報(bao)警，表示(shi)西(xi)門子(zi)NCU維修(xiu)啟動(dong)之后，未進(jin)行機床回基準(zhun)點的(de)操作，系統處于自(zi)動(dong)保持狀態。