一(yi)、開關電源(yuan)一(yi)直(zhi)無(wu)電壓輸出的檢修技巧(qiao)

開關(guan)(guan)(guan)(guan)電(dian)(dian)源一(yi)直(zhi)無電(dian)(dian)壓輸出(chu)是(shi)指開關(guan)(guan)(guan)(guan)電(dian)(dian)源各輸出(chu)端，在按(an)電(dian)(dian)源開關(guan)(guan)(guan)(guan)開機(ji)后(hou)一(yi)直(zhi)為(wei)(wei)0V，這(zhe)種狀況是(shi)因為(wei)(wei)開關(guan)(guan)(guan)(guan)電(dian)(dian)源未(wei)(wei)發生(sheng)(sheng)震(zhen)蕩所致。進一(yi)步證明的(de)辦(ban)法是(shi)測開關(guan)(guan)(guan)(guan)電(dian)(dian)源100UF/400V電(dian)(dian)容(rong)關(guan)(guan)(guan)(guan)機(ji)后(hou)的(de)電(dian)(dian)壓，若(ruo)300V之后(hou)慢慢下降，則闡明開關(guan)(guan)(guan)(guan)電(dian)(dian)源未(wei)(wei)發生(sheng)(sheng)振(zhen)動(dong)。開關(guan)(guan)(guan)(guan)電(dian)(dian)源未(wei)(wei)發生(sheng)(sheng)振(zhen)動(dong)的(de)原因有(you)：

(1)開(kai)關(guan)管集電極未得到滿足(zu)的(de)作業(ye)電壓

(2)開關管(guan)基(ji)極未(wei)得到發動電壓和相關電路漏電

(3)開關(guan)管正反饋元件失效

判(pan)別毛病的辦法(fa)和(he)過程

檢修這類(lei)毛病(bing)的(de)首要(yao)任務是判別毛病(bing)在上述三個部位(wei)中的(de)哪個部位(wei)，具體辦法是測(ce)開關管集電(dian)極，基極電(dian)壓，可能有以下(xia)幾種(zhong)狀況：

(1)開關(guan)(guan)管(guan)集電(dian)極電(dian)壓(ya)(ya)為0V和(he)低(di)于市(shi)電(dian)1.4倍(bei)，開關(guan)(guan)管(guan)沒有(you)正常(chang)的(de)作(zuo)業(ye)電(dian)壓(ya)(ya)，如果有(you)1.4倍(bei)的(de)電(dian)壓(ya)(ya)，闡明開關(guan)(guan)管(guan)集電(dian)極具有(you)了正常(chang)的(de)作(zuo)業(ye)電(dian)壓(ya)(ya)，闡明AC220V及整流濾波電(dian)路(lu)作(zuo)業(ye)正常(chang)。

(2)開關(guan)(guan)(guan)管(guan)的基極(ji)電(dian)(dian)(dian)壓(ya)為0V(包(bao)(bao)含開機(ji)瞬間(jian))這種狀況(kuang)闡(chan)明(ming)發(fa)動電(dian)(dian)(dian)路對開關(guan)(guan)(guan)管(guan)基極(ji)未(wei)提供(gong)發(fa)動(導通)電(dian)(dian)(dian)壓(ya)，或基極(ji)與發(fa)射極(ji)之間(jian)相關(guan)(guan)(guan)元(yuan)件擊(ji)穿，應對發(fa)動電(dian)(dian)(dian)路和開關(guan)(guan)(guan)管(guan)發(fa)射極(ji)及(ji)相關(guan)(guan)(guan)元(yuan)件進行查看，若電(dian)(dian)(dian)壓(ya)為0.6~0.7(包(bao)(bao)含開機(ji)瞬間(jian))，闡(chan)明(ming)發(fa)動電(dian)(dian)(dian)路和開關(guan)(guan)(guan)管(guan)發(fa)射極(ji)元(yuan)件正(zheng)常，若在(zai)0.7V以(yi)上闡(chan)明(ming)發(fa)動電(dian)(dian)(dian)路正(zheng)常，但開關(guan)(guan)(guan)管(guan)發(fa)射極(ji)或其(qi)元(yuan)件斷(duan)路或阻值變大。

(3)開關(guan)管(guan)具(ju)有(you)導通條件：開關(guan)管(guan)基極電(dian)壓為0.6~0.7V，集(ji)電(dian)極電(dian)壓大(da)于250V，闡明開關(guan)管(guan)具(ju)有(you)了作業(ye)條件，毛病在正(zheng)反(fan)饋電(dian)路，包含正(zheng)反(fan)饋電(dian)阻，電(dian)容(rong)，續(xu)流二極管(guan)及(ji)開關(guan)變壓器(qi)正(zheng)反(fan)饋繞組及(ji)其(qi)之間的銜接應制板。

開(kai)關電源瞬間(jian)有電壓出檢修技巧

1）、瞬間電壓輸出(chu)毛(mao)病原因

這(zhe)(zhe)種毛病(bing)在按下發動開(kai)關的瞬(shun)間，開(kai)關電(dian)源(yuan)某(mou)個(ge)或各(ge)個(ge)輸(shu)出端(duan)電(dian)壓有(you)一個(ge)小的電(dian)壓輸(shu)出，然后降(jiang)為0V，這(zhe)(zhe)種狀(zhuang)(zhuang)況(kuang)闡明開(kai)關電(dian)源(yuan)在加電(dian)的初始(shi)發生了振動，但后因為過(guo)壓，過(guo)流(liu)維護引(yin)起停振，或開(kai)關機接(jie)口電(dian)路加電(dian)初始(shi)為開(kai)機狀(zhuang)(zhuang)況(kuang)，但隨CPU清零的完畢而轉入待機狀(zhuang)(zhuang)況(kuang)，引(yin)發這(zhe)(zhe)種狀(zhuang)(zhuang)況(kuang)的原(yuan)因有(you)：

(1)開關電(dian)源因故輸出(chu)電(dian)壓(ya)比標準(zhun)值(zhi)高10V而引起過壓(ya)維護

(2)負載過流引起維護(hu)動作

(3)維護電(dian)路自身的誤動作

(4)遙控系統(tong)因(yin)故執行待機指令

2）、判別毛病辦(ban)法與過程

（1）假負載法

（2）測量維(wei)護元件(jian)是否擊穿

（3）斷開法

（4）降壓法

3）、各功(gong)用電路的(de)檢測辦(ban)法

經過上述辦法判別毛病在開關電源的哪個(ge)部(bu)分后(hou)，對各個(ge)部(bu)分的查看(kan)辦法如下(xia)：

（1）對脈寬調(diao)制電(dian)(dian)(dian)(dian)路和正(zheng)反(fan)饋(kui)電(dian)(dian)(dian)(dian)路的(de)(de)查(cha)看(kan)。對正(zheng)反(fan)饋(kui)電(dian)(dian)(dian)(dian)路中(zhong)的(de)(de)電(dian)(dian)(dian)(dian)解(jie)電(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)直接替換現在開關電(dian)(dian)(dian)(dian)源的(de)(de)正(zheng)反(fan)饋(kui)電(dian)(dian)(dian)(dian)路中(zhong)的(de)(de)振動電(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)有兩種，一(yi)是0。016UF0。039UF膽電(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)，其毛病率(lv)很低，檢(jian)修這種電(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)可以掃除，另一(yi)種是10UF左右的(de)(de)電(dian)(dian)(dian)(dian)解(jie)電(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)，毛病率(lv)使用(yong)數年(nian)后有可能，檢(jian)修時直接替換此電(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)。

（2）替換脈寬(kuan)調制電路(lu)作業電壓形成中的電解電容(rong)

在手(shou)中無溝通調(diao)壓(ya)器的狀況下，對于過壓(ya)維護毛(mao)病，為了安全起見可先替換脈寬調(diao)制電(dian)(dian)路(lu)作業電(dian)(dian)壓(ya)形成電(dian)(dian)路(lu)中的易損件，即濾波電(dian)(dian)容（幾微(wei)法(fa)到100UF不等的電(dian)(dian)解電(dian)(dian)容），看開關(guan)電(dian)(dian)源是否康復正常。

開關電源(yuan)輸出電壓低檢修技巧(qiao)

1、開關(guan)電源輸(shu)出電壓低的(de)原因

（1）220V溝(gou)通電(dian)(dian)壓輸入電(dian)(dian)路(lu)和整流濾波電(dian)(dian)路(lu)對開(kai)關(guan)管提供的作業電(dian)(dian)壓不夠，超出(chu)脈寬調制電(dian)(dian)路(lu)的控制范圍。

（2）負(fu)載(zai)電(dian)路存在過流引(yin)起開關電(dian)源負(fu)載(zai)加重而導致(zhi)輸出(chu)電(dian)壓下降(jiang)。

（3）開/關機接口電路(lu)處(chu)于待機狀(zhuang)(zhuang)況，令(ling)開關電源作(zuo)業于低頻振動狀(zhuang)(zhuang)況其輸出電壓為(wei)待機狀(zhuang)(zhuang)況下的度(du)數(shu)。此(ci)類毛(mao)病(bing)僅應于無準備電源，CPU準備狀(zhuang)(zhuang)況下的作(zuo)業電壓由(you)開關電源提供的機型。