一、開關電源一直無(wu)電壓(ya)輸出的(de)檢修技巧

開(kai)(kai)(kai)關(guan)(guan)(guan)電(dian)(dian)源(yuan)一直無電(dian)(dian)壓輸出是(shi)指開(kai)(kai)(kai)關(guan)(guan)(guan)電(dian)(dian)源(yuan)各輸出端(duan)，在按電(dian)(dian)源(yuan)開(kai)(kai)(kai)關(guan)(guan)(guan)開(kai)(kai)(kai)機后一直為(wei)0V，這(zhe)種狀況(kuang)是(shi)因(yin)為(wei)開(kai)(kai)(kai)關(guan)(guan)(guan)電(dian)(dian)源(yuan)未發生震(zhen)蕩所致。進一步證明的辦法是(shi)測開(kai)(kai)(kai)關(guan)(guan)(guan)電(dian)(dian)源(yuan)100UF/400V電(dian)(dian)容關(guan)(guan)(guan)機后的電(dian)(dian)壓，若300V之后慢慢下降，則闡明開(kai)(kai)(kai)關(guan)(guan)(guan)電(dian)(dian)源(yuan)未發生振動。開(kai)(kai)(kai)關(guan)(guan)(guan)電(dian)(dian)源(yuan)未發生振動的原因(yin)有(you)：

(1)開(kai)關(guan)管集電極(ji)未得到滿足的作業電壓

(2)開關(guan)管(guan)基極未得到發(fa)動電(dian)壓和相(xiang)關(guan)電(dian)路漏(lou)電(dian)

(3)開關(guan)管正反饋元件失效

判(pan)別毛病的辦(ban)法和過程

檢修這類毛(mao)病(bing)的首要任務(wu)是判別毛(mao)病(bing)在上述三(san)個部位(wei)中的哪個部位(wei)，具體辦法是測開關管(guan)集電極(ji)(ji)，基(ji)極(ji)(ji)電壓(ya)，可能(neng)有以下(xia)幾種狀況：

(1)開(kai)關(guan)(guan)管(guan)集(ji)電(dian)極(ji)電(dian)壓(ya)為0V和低于市(shi)電(dian)1.4倍(bei)，開(kai)關(guan)(guan)管(guan)沒有正常的(de)(de)作(zuo)業電(dian)壓(ya)，如果有1.4倍(bei)的(de)(de)電(dian)壓(ya)，闡明開(kai)關(guan)(guan)管(guan)集(ji)電(dian)極(ji)具(ju)有了(le)正常的(de)(de)作(zuo)業電(dian)壓(ya)，闡明AC220V及整流濾波電(dian)路作(zuo)業正常。

(2)開(kai)關(guan)(guan)(guan)(guan)管(guan)的基極(ji)電(dian)(dian)壓為0V(包(bao)含(han)開(kai)機瞬間)這種狀況闡明(ming)發(fa)動(dong)(dong)(dong)電(dian)(dian)路(lu)(lu)對開(kai)關(guan)(guan)(guan)(guan)管(guan)基極(ji)未提供(gong)發(fa)動(dong)(dong)(dong)(導通)電(dian)(dian)壓，或基極(ji)與發(fa)射(she)(she)極(ji)之間相(xiang)關(guan)(guan)(guan)(guan)元(yuan)件(jian)擊穿，應對發(fa)動(dong)(dong)(dong)電(dian)(dian)路(lu)(lu)和(he)開(kai)關(guan)(guan)(guan)(guan)管(guan)發(fa)射(she)(she)極(ji)及相(xiang)關(guan)(guan)(guan)(guan)元(yuan)件(jian)進行查看，若(ruo)電(dian)(dian)壓為0.6~0.7(包(bao)含(han)開(kai)機瞬間)，闡明(ming)發(fa)動(dong)(dong)(dong)電(dian)(dian)路(lu)(lu)和(he)開(kai)關(guan)(guan)(guan)(guan)管(guan)發(fa)射(she)(she)極(ji)元(yuan)件(jian)正常(chang)(chang)，若(ruo)在(zai)0.7V以上闡明(ming)發(fa)動(dong)(dong)(dong)電(dian)(dian)路(lu)(lu)正常(chang)(chang)，但開(kai)關(guan)(guan)(guan)(guan)管(guan)發(fa)射(she)(she)極(ji)或其(qi)元(yuan)件(jian)斷路(lu)(lu)或阻(zu)值(zhi)變大。

(3)開(kai)關管具(ju)有導通條(tiao)(tiao)件(jian)：開(kai)關管基極(ji)電(dian)壓(ya)為(wei)0.6~0.7V，集電(dian)極(ji)電(dian)壓(ya)大于250V，闡(chan)明(ming)開(kai)關管具(ju)有了作業條(tiao)(tiao)件(jian)，毛病在正反(fan)饋電(dian)路，包含(han)正反(fan)饋電(dian)阻，電(dian)容，續流二極(ji)管及開(kai)關變(bian)壓(ya)器正反(fan)饋繞(rao)組(zu)及其之間的銜(xian)接(jie)應制板。

開關電源瞬(shun)間有電壓出檢(jian)修技巧(qiao)

1）、瞬(shun)間(jian)電壓(ya)輸(shu)出毛病原因

這(zhe)種(zhong)毛病在按下發(fa)動開(kai)關(guan)(guan)的瞬間，開(kai)關(guan)(guan)電(dian)(dian)源(yuan)某個或(huo)各個輸(shu)出端電(dian)(dian)壓有一個小的電(dian)(dian)壓輸(shu)出，然(ran)后降為(wei)0V，這(zhe)種(zhong)狀況(kuang)闡(chan)明開(kai)關(guan)(guan)電(dian)(dian)源(yuan)在加(jia)電(dian)(dian)的初始(shi)發(fa)生了振(zhen)動，但(dan)后因為(wei)過壓，過流維護(hu)引起停振(zhen)，或(huo)開(kai)關(guan)(guan)機(ji)接口(kou)電(dian)(dian)路加(jia)電(dian)(dian)初始(shi)為(wei)開(kai)機(ji)狀況(kuang)，但(dan)隨CPU清(qing)零的完畢而轉(zhuan)入(ru)待機(ji)狀況(kuang)，引發(fa)這(zhe)種(zhong)狀況(kuang)的原因有：

(1)開關電源因故(gu)輸出電壓(ya)比標準(zhun)值高10V而引起過壓(ya)維護

(2)負載過流引起(qi)維護動作(zuo)

(3)維護電(dian)路(lu)自身的誤動作

(4)遙(yao)控系統因故執行待機指令

2）、判別(bie)毛病辦法與過程

（1）假負載法

（2）測量維護元(yuan)件是否擊(ji)穿

（3）斷開法

（4）降壓法

3）、各功用電(dian)路的檢測(ce)辦法

經過上述辦(ban)法判別毛病在開關電源的哪個部分后，對各個部分的查(cha)看辦(ban)法如(ru)下：

（1）對脈寬調制電(dian)(dian)路(lu)和正(zheng)反(fan)饋電(dian)(dian)路(lu)的(de)(de)查看。對正(zheng)反(fan)饋電(dian)(dian)路(lu)中(zhong)(zhong)的(de)(de)電(dian)(dian)解電(dian)(dian)容(rong)(rong)直(zhi)接替(ti)換現在開關(guan)電(dian)(dian)源的(de)(de)正(zheng)反(fan)饋電(dian)(dian)路(lu)中(zhong)(zhong)的(de)(de)振動(dong)電(dian)(dian)容(rong)(rong)有兩種，一是(shi)0。016UF0。039UF膽電(dian)(dian)容(rong)(rong)，其毛病(bing)率很(hen)低，檢修這種電(dian)(dian)容(rong)(rong)可以掃(sao)除(chu)，另一種是(shi)10UF左右的(de)(de)電(dian)(dian)解電(dian)(dian)容(rong)(rong)，毛病(bing)率使用數年后有可能(neng)，檢修時直(zhi)接替(ti)換此(ci)電(dian)(dian)容(rong)(rong)。

（2）替換脈(mo)寬調制(zhi)電(dian)路作業電(dian)壓形成中的電(dian)解電(dian)容(rong)

在手中(zhong)無溝通調壓器的狀(zhuang)況(kuang)下，對(dui)于(yu)過壓維護毛病，為了安全起見(jian)可先替換(huan)脈寬調制電(dian)(dian)(dian)路(lu)作業(ye)電(dian)(dian)(dian)壓形成電(dian)(dian)(dian)路(lu)中(zhong)的易損件，即(ji)濾波電(dian)(dian)(dian)容（幾微法到(dao)100UF不等的電(dian)(dian)(dian)解電(dian)(dian)(dian)容），看開(kai)關電(dian)(dian)(dian)源是(shi)否康復正常。

開關電(dian)源輸出電(dian)壓低檢修技巧

1、開關(guan)電源輸出電壓低的原因

（1）220V溝通電(dian)(dian)壓(ya)輸入(ru)電(dian)(dian)路和整流濾波電(dian)(dian)路對開關(guan)管提供的作業電(dian)(dian)壓(ya)不夠，超出(chu)脈寬(kuan)調制電(dian)(dian)路的控制范圍。

（2）負載電路存在(zai)過流引起開關電源負載加重而導(dao)致輸出電壓下降(jiang)。

（3）開/關機(ji)接口電(dian)(dian)(dian)路處于(yu)(yu)待(dai)機(ji)狀況，令開關電(dian)(dian)(dian)源作(zuo)業于(yu)(yu)低頻(pin)振動狀況其輸出電(dian)(dian)(dian)壓為待(dai)機(ji)狀況下的度數。此類毛病僅應于(yu)(yu)無準(zhun)備(bei)電(dian)(dian)(dian)源，CPU準(zhun)備(bei)狀況下的作(zuo)業電(dian)(dian)(dian)壓由開關電(dian)(dian)(dian)源提供的機(ji)型。