一(yi)(yi)、開關電(dian)源一(yi)(yi)直(zhi)無電(dian)壓(ya)輸出的檢修技巧

開(kai)(kai)(kai)(kai)(kai)關(guan)電(dian)(dian)(dian)源(yuan)(yuan)(yuan)一直無電(dian)(dian)(dian)壓(ya)輸(shu)出是指開(kai)(kai)(kai)(kai)(kai)關(guan)電(dian)(dian)(dian)源(yuan)(yuan)(yuan)各輸(shu)出端，在(zai)按電(dian)(dian)(dian)源(yuan)(yuan)(yuan)開(kai)(kai)(kai)(kai)(kai)關(guan)開(kai)(kai)(kai)(kai)(kai)機后(hou)一直為(wei)0V，這種狀況是因為(wei)開(kai)(kai)(kai)(kai)(kai)關(guan)電(dian)(dian)(dian)源(yuan)(yuan)(yuan)未(wei)發生(sheng)震(zhen)蕩所致。進一步(bu)證明(ming)的(de)辦(ban)法是測開(kai)(kai)(kai)(kai)(kai)關(guan)電(dian)(dian)(dian)源(yuan)(yuan)(yuan)100UF/400V電(dian)(dian)(dian)容關(guan)機后(hou)的(de)電(dian)(dian)(dian)壓(ya)，若(ruo)300V之后(hou)慢慢下降，則闡明(ming)開(kai)(kai)(kai)(kai)(kai)關(guan)電(dian)(dian)(dian)源(yuan)(yuan)(yuan)未(wei)發生(sheng)振動。開(kai)(kai)(kai)(kai)(kai)關(guan)電(dian)(dian)(dian)源(yuan)(yuan)(yuan)未(wei)發生(sheng)振動的(de)原(yuan)因有：

(1)開關管集電極未得到滿(man)足的作業(ye)電壓

(2)開關管基極未得到發(fa)動電(dian)壓和(he)相關電(dian)路漏(lou)電(dian)

(3)開關管正反饋元件失效

判別毛病的辦(ban)法和過程

檢(jian)修這類毛病(bing)的首要(yao)任務是判別(bie)毛病(bing)在上述三個(ge)部位中的哪個(ge)部位，具體辦(ban)法是測(ce)開關管(guan)集電極，基(ji)極電壓，可(ke)能有以(yi)下幾種(zhong)狀況(kuang)：

(1)開(kai)關管(guan)集(ji)(ji)電極電壓為0V和低于(yu)市電1.4倍，開(kai)關管(guan)沒有正常(chang)(chang)的(de)作業(ye)電壓，如果(guo)有1.4倍的(de)電壓，闡明開(kai)關管(guan)集(ji)(ji)電極具(ju)有了正常(chang)(chang)的(de)作業(ye)電壓，闡明AC220V及整流濾波電路作業(ye)正常(chang)(chang)。

(2)開(kai)(kai)(kai)(kai)關管的基(ji)極(ji)電(dian)(dian)(dian)(dian)壓(ya)(ya)為0V(包含開(kai)(kai)(kai)(kai)機瞬間(jian))這種狀況闡(chan)明(ming)(ming)發動(dong)電(dian)(dian)(dian)(dian)路(lu)對(dui)開(kai)(kai)(kai)(kai)關管基(ji)極(ji)未提供發動(dong)(導(dao)通)電(dian)(dian)(dian)(dian)壓(ya)(ya)，或基(ji)極(ji)與發射極(ji)之(zhi)間(jian)相(xiang)關元(yuan)件(jian)擊穿，應對(dui)發動(dong)電(dian)(dian)(dian)(dian)路(lu)和開(kai)(kai)(kai)(kai)關管發射極(ji)及相(xiang)關元(yuan)件(jian)進行查看(kan)，若電(dian)(dian)(dian)(dian)壓(ya)(ya)為0.6~0.7(包含開(kai)(kai)(kai)(kai)機瞬間(jian))，闡(chan)明(ming)(ming)發動(dong)電(dian)(dian)(dian)(dian)路(lu)和開(kai)(kai)(kai)(kai)關管發射極(ji)元(yuan)件(jian)正常，若在0.7V以上闡(chan)明(ming)(ming)發動(dong)電(dian)(dian)(dian)(dian)路(lu)正常，但開(kai)(kai)(kai)(kai)關管發射極(ji)或其(qi)元(yuan)件(jian)斷(duan)路(lu)或阻值變大。

(3)開(kai)關管(guan)(guan)(guan)具(ju)有導(dao)通條件：開(kai)關管(guan)(guan)(guan)基極電(dian)(dian)(dian)(dian)壓為0.6~0.7V，集電(dian)(dian)(dian)(dian)極電(dian)(dian)(dian)(dian)壓大于(yu)250V，闡(chan)明(ming)開(kai)關管(guan)(guan)(guan)具(ju)有了(le)作業條件，毛病在正(zheng)反(fan)饋電(dian)(dian)(dian)(dian)路，包含正(zheng)反(fan)饋電(dian)(dian)(dian)(dian)阻，電(dian)(dian)(dian)(dian)容，續(xu)流二極管(guan)(guan)(guan)及開(kai)關變壓器正(zheng)反(fan)饋繞(rao)組(zu)及其之間(jian)的銜(xian)接應制板。

開(kai)關電源瞬間有電壓出檢修技巧

1）、瞬間電壓輸出毛病(bing)原因

這種(zhong)毛病在按下(xia)發動開(kai)關的(de)瞬間(jian)，開(kai)關電(dian)(dian)源(yuan)某個或各個輸(shu)出(chu)端電(dian)(dian)壓(ya)(ya)有一個小(xiao)的(de)電(dian)(dian)壓(ya)(ya)輸(shu)出(chu)，然后(hou)降為0V，這種(zhong)狀況闡明開(kai)關電(dian)(dian)源(yuan)在加電(dian)(dian)的(de)初始發生了振動，但后(hou)因為過壓(ya)(ya)，過流維(wei)護引起(qi)停振，或開(kai)關機(ji)接(jie)口電(dian)(dian)路加電(dian)(dian)初始為開(kai)機(ji)狀況，但隨CPU清零的(de)完(wan)畢(bi)而轉(zhuan)入待機(ji)狀況，引發這種(zhong)狀況的(de)原因有：

(1)開關電(dian)源(yuan)因故輸出(chu)電(dian)壓(ya)比標準值高10V而引起過(guo)壓(ya)維護

(2)負載過(guo)流引(yin)起維護(hu)動作

(3)維(wei)護電路(lu)自身的誤動(dong)作

(4)遙(yao)控系統因故執行(xing)待(dai)機指令(ling)

2）、判別毛病辦法與過(guo)程(cheng)

（1）假負載法

（2）測(ce)量(liang)維護元件是否擊穿

（3）斷開法

（4）降壓法

3）、各功用(yong)電路(lu)的檢測辦法

經過上(shang)述(shu)辦(ban)法判(pan)別毛病在(zai)開(kai)關(guan)電源的(de)哪(na)個部(bu)分后，對各個部(bu)分的(de)查看辦(ban)法如下：

（1）對脈寬(kuan)調制電(dian)(dian)路和正(zheng)(zheng)反(fan)饋電(dian)(dian)路的(de)(de)查看。對正(zheng)(zheng)反(fan)饋電(dian)(dian)路中的(de)(de)電(dian)(dian)解電(dian)(dian)容(rong)直接替換現在開關電(dian)(dian)源(yuan)的(de)(de)正(zheng)(zheng)反(fan)饋電(dian)(dian)路中的(de)(de)振(zhen)動電(dian)(dian)容(rong)有兩種(zhong)，一是0。016UF0。039UF膽電(dian)(dian)容(rong)，其毛(mao)(mao)病(bing)率很低，檢修這種(zhong)電(dian)(dian)容(rong)可(ke)以掃除，另一種(zhong)是10UF左右的(de)(de)電(dian)(dian)解電(dian)(dian)容(rong)，毛(mao)(mao)病(bing)率使用數年(nian)后有可(ke)能，檢修時直接替換此電(dian)(dian)容(rong)。

（2）替換脈寬調制電路作業電壓形成中的電解電容(rong)

在(zai)手中無(wu)溝通調壓器(qi)的(de)狀況下(xia)，對于過壓維護毛病，為了安全起見可先替換脈寬(kuan)調制電(dian)(dian)路作業電(dian)(dian)壓形成電(dian)(dian)路中的(de)易損(sun)件，即濾波電(dian)(dian)容(rong)（幾微法(fa)到(dao)100UF不等的(de)電(dian)(dian)解(jie)電(dian)(dian)容(rong)），看開關電(dian)(dian)源是否康復正常。

開關電(dian)源(yuan)輸出電(dian)壓低檢(jian)修(xiu)技巧

1、開關電源輸出電壓低的原因

（1）220V溝(gou)通(tong)電(dian)(dian)壓輸(shu)入電(dian)(dian)路和整流濾(lv)波電(dian)(dian)路對(dui)開關管提供的(de)作業電(dian)(dian)壓不夠，超出脈寬調(diao)制電(dian)(dian)路的(de)控制范圍。

（2）負(fu)載(zai)電(dian)路存在(zai)過流引起開關電(dian)源負(fu)載(zai)加重而(er)導致輸出(chu)電(dian)壓(ya)下(xia)降。

（3）開(kai)/關機(ji)接(jie)口電(dian)路處于待機(ji)狀(zhuang)況(kuang)，令開(kai)關電(dian)源(yuan)(yuan)作(zuo)業于低(di)頻振動(dong)狀(zhuang)況(kuang)其(qi)輸出電(dian)壓為待機(ji)狀(zhuang)況(kuang)下的(de)(de)度數。此類(lei)毛病僅(jin)應(ying)于無準(zhun)備電(dian)源(yuan)(yuan)，CPU準(zhun)備狀(zhuang)況(kuang)下的(de)(de)作(zuo)業電(dian)壓由開(kai)關電(dian)源(yuan)(yuan)提供(gong)的(de)(de)機(ji)型。