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

開(kai)(kai)關(guan)(guan)電(dian)源(yuan)一直(zhi)無電(dian)壓輸(shu)出是(shi)指開(kai)(kai)關(guan)(guan)電(dian)源(yuan)各(ge)輸(shu)出端，在按電(dian)源(yuan)開(kai)(kai)關(guan)(guan)開(kai)(kai)機(ji)后(hou)一直(zhi)為0V，這種狀況是(shi)因為開(kai)(kai)關(guan)(guan)電(dian)源(yuan)未發(fa)(fa)生震蕩所致。進(jin)一步證(zheng)明的(de)辦法是(shi)測開(kai)(kai)關(guan)(guan)電(dian)源(yuan)100UF/400V電(dian)容關(guan)(guan)機(ji)后(hou)的(de)電(dian)壓，若(ruo)300V之后(hou)慢(man)慢(man)下(xia)降(jiang)，則(ze)闡明開(kai)(kai)關(guan)(guan)電(dian)源(yuan)未發(fa)(fa)生振(zhen)動(dong)(dong)。開(kai)(kai)關(guan)(guan)電(dian)源(yuan)未發(fa)(fa)生振(zhen)動(dong)(dong)的(de)原(yuan)因有：

(1)開關管(guan)集電(dian)極未得到滿足的作業電(dian)壓

(2)開關(guan)管基(ji)極未得到發動電(dian)壓和相關(guan)電(dian)路漏電(dian)

(3)開關管正(zheng)反饋元件(jian)失效

判別毛病的辦法和過程(cheng)

檢修這類毛病的(de)(de)首要任務是判別毛病在(zai)上(shang)述三(san)個部位中的(de)(de)哪個部位，具體辦(ban)法是測開關管集電極，基極電壓(ya)，可能有以下幾種狀況：

(1)開關管集電(dian)(dian)極電(dian)(dian)壓(ya)為0V和低于市(shi)電(dian)(dian)1.4倍，開關管沒有(you)正常(chang)的作業電(dian)(dian)壓(ya)，如果有(you)1.4倍的電(dian)(dian)壓(ya)，闡明開關管集電(dian)(dian)極具有(you)了正常(chang)的作業電(dian)(dian)壓(ya)，闡明AC220V及整流濾波電(dian)(dian)路作業正常(chang)。

(2)開(kai)關(guan)(guan)管(guan)(guan)(guan)的(de)基(ji)極電(dian)壓為0V(包(bao)(bao)含(han)開(kai)機瞬(shun)(shun)間(jian))這種狀況闡明(ming)(ming)發(fa)動電(dian)路對(dui)開(kai)關(guan)(guan)管(guan)(guan)(guan)基(ji)極未提供發(fa)動(導(dao)通)電(dian)壓，或(huo)基(ji)極與發(fa)射(she)極之間(jian)相關(guan)(guan)元(yuan)件擊穿，應(ying)對(dui)發(fa)動電(dian)路和(he)(he)開(kai)關(guan)(guan)管(guan)(guan)(guan)發(fa)射(she)極及(ji)相關(guan)(guan)元(yuan)件進行(xing)查看，若電(dian)壓為0.6~0.7(包(bao)(bao)含(han)開(kai)機瞬(shun)(shun)間(jian))，闡明(ming)(ming)發(fa)動電(dian)路和(he)(he)開(kai)關(guan)(guan)管(guan)(guan)(guan)發(fa)射(she)極元(yuan)件正常，若在(zai)0.7V以上闡明(ming)(ming)發(fa)動電(dian)路正常，但開(kai)關(guan)(guan)管(guan)(guan)(guan)發(fa)射(she)極或(huo)其元(yuan)件斷路或(huo)阻值變大。

(3)開關(guan)(guan)(guan)管(guan)具有導(dao)通條件：開關(guan)(guan)(guan)管(guan)基極(ji)(ji)電(dian)壓為(wei)0.6~0.7V，集(ji)電(dian)極(ji)(ji)電(dian)壓大于(yu)250V，闡明(ming)開關(guan)(guan)(guan)管(guan)具有了作業條件，毛病在正反(fan)饋(kui)電(dian)路，包含正反(fan)饋(kui)電(dian)阻，電(dian)容(rong)，續(xu)流二極(ji)(ji)管(guan)及開關(guan)(guan)(guan)變壓器正反(fan)饋(kui)繞組及其之間的銜接應制板。

開關電源瞬(shun)間有電壓出檢修技巧

1）、瞬間電壓輸出毛(mao)病原(yuan)因

這(zhe)種(zhong)毛(mao)病在按下發(fa)動開(kai)關(guan)的(de)瞬(shun)間，開(kai)關(guan)電源某個或(huo)各(ge)個輸(shu)出(chu)端電壓有一個小的(de)電壓輸(shu)出(chu)，然后降為0V，這(zhe)種(zhong)狀況闡明開(kai)關(guan)電源在加(jia)電的(de)初(chu)始發(fa)生(sheng)了振(zhen)動，但(dan)后因(yin)為過(guo)壓，過(guo)流維(wei)護引起停振(zhen)，或(huo)開(kai)關(guan)機接口(kou)電路(lu)加(jia)電初(chu)始為開(kai)機狀況，但(dan)隨CPU清零的(de)完畢而轉入(ru)待機狀況，引發(fa)這(zhe)種(zhong)狀況的(de)原因(yin)有：

(1)開關電源因故輸出電壓比標準值高10V而(er)引起過(guo)壓維護

(2)負載過(guo)流(liu)引起維護動作

(3)維護(hu)電路自身(shen)的誤動作

(4)遙(yao)控(kong)系統因故執行待機指令(ling)

2）、判別毛(mao)病(bing)辦法與過(guo)程

（1）假負載法

（2）測(ce)量維護元件(jian)是否擊穿

（3）斷開法

（4）降壓法

3）、各功用電路(lu)的(de)檢測辦法

經過上述辦(ban)(ban)法判(pan)別毛(mao)病在開關電源的哪個(ge)部分后，對各個(ge)部分的查看辦(ban)(ban)法如下：

（1）對脈(mo)寬調制(zhi)電(dian)(dian)(dian)(dian)路(lu)(lu)(lu)和(he)正(zheng)反(fan)饋(kui)(kui)電(dian)(dian)(dian)(dian)路(lu)(lu)(lu)的查看。對正(zheng)反(fan)饋(kui)(kui)電(dian)(dian)(dian)(dian)路(lu)(lu)(lu)中的電(dian)(dian)(dian)(dian)解電(dian)(dian)(dian)(dian)容直(zhi)接替(ti)(ti)換現在開關電(dian)(dian)(dian)(dian)源的正(zheng)反(fan)饋(kui)(kui)電(dian)(dian)(dian)(dian)路(lu)(lu)(lu)中的振(zhen)動(dong)電(dian)(dian)(dian)(dian)容有兩種(zhong)，一是0。016UF0。039UF膽(dan)電(dian)(dian)(dian)(dian)容，其毛病率很低，檢修這種(zhong)電(dian)(dian)(dian)(dian)容可(ke)(ke)以掃(sao)除，另一種(zhong)是10UF左右的電(dian)(dian)(dian)(dian)解電(dian)(dian)(dian)(dian)容，毛病率使用數年后有可(ke)(ke)能，檢修時直(zhi)接替(ti)(ti)換此電(dian)(dian)(dian)(dian)容。

（2）替換脈寬調制電路(lu)作業電壓形成(cheng)中的電解電容

在手中無溝(gou)通調壓(ya)器的(de)(de)狀(zhuang)況下，對(dui)于(yu)過壓(ya)維護毛(mao)病，為了安全起見可先替換(huan)脈寬調制電(dian)(dian)(dian)(dian)路作業電(dian)(dian)(dian)(dian)壓(ya)形成電(dian)(dian)(dian)(dian)路中的(de)(de)易(yi)損(sun)件，即濾波(bo)電(dian)(dian)(dian)(dian)容(rong)（幾微(wei)法(fa)到(dao)100UF不等(deng)的(de)(de)電(dian)(dian)(dian)(dian)解電(dian)(dian)(dian)(dian)容(rong)），看開(kai)關電(dian)(dian)(dian)(dian)源是否康復正常。

開(kai)關電(dian)源輸(shu)出電(dian)壓低檢(jian)修技巧

1、開(kai)關電源(yuan)輸出電壓(ya)低(di)的原因(yin)

（1）220V溝通(tong)電壓輸入電路(lu)和整(zheng)流濾波(bo)電路(lu)對開關管提供的作業電壓不夠，超(chao)出脈(mo)寬(kuan)調(diao)制電路(lu)的控制范圍。

（2）負載(zai)電(dian)路(lu)存在過流引起開關電(dian)源負載(zai)加(jia)重而導致(zhi)輸出(chu)電(dian)壓(ya)下(xia)降。

（3）開(kai)(kai)/關(guan)機(ji)接口電路處于(yu)待(dai)機(ji)狀況(kuang)，令開(kai)(kai)關(guan)電源作(zuo)業于(yu)低(di)頻(pin)振動狀況(kuang)其輸出電壓(ya)(ya)為待(dai)機(ji)狀況(kuang)下的(de)度數。此類毛(mao)病僅應(ying)于(yu)無準備(bei)電源，CPU準備(bei)狀況(kuang)下的(de)作(zuo)業電壓(ya)(ya)由開(kai)(kai)關(guan)電源提供的(de)機(ji)型。