一般情況(kuang)下，電源適配器出現(xian)故障(zhang)(zhang)的情況多(duo)是(shi)這三種：1、高壓故障(zhang)(zhang)2、低壓故障(zhang)(zhang)3、高壓低壓均有故障(zhang)(zhang)。

高壓(ya)(ya)故(gu)障的(de)主(zhu)要現象是(shi)(shi)指示燈(deng)不(bu)亮，其(qi)特(te)征有(you)保險絲熔斷，整(zheng)流二極管D1擊(ji)穿，電(dian)容C11鼓包或炸裂。Q1擊(ji)穿,R25開(kai)路(lu)。U1的(de)7腳(jiao)對(dui)地短路(lu)。R5開(kai)路(lu)，U1無啟動(dong)電(dian)壓(ya)(ya)。更換以(yi)上(shang)(shang)元件即可修復。若(ruo)(ruo)U1的(de)7腳(jiao)有(you)11V以(yi)上(shang)(shang)電(dian)壓(ya)(ya)，8腳(jiao)有(you)5V電(dian)壓(ya)(ya)，說明U1基本正常(chang)(chang)。應(ying)重(zhong)點檢測(ce)Q1和T1的(de)引(yin)腳(jiao)是(shi)(shi)否有(you)虛焊(han)(han)。若(ruo)(ruo)連續擊(ji)穿Q1，且(qie)Q1不(bu)發燙，一般(ban)是(shi)(shi)D2,C4失效(xiao)，若(ruo)(ruo)是(shi)(shi)Q1擊(ji)穿且(qie)發燙，一般(ban)是(shi)(shi)低(di)壓(ya)(ya)部分有(you)漏電(dian)或短路(lu)，過(guo)大(da)或UC3842的(de)6腳(jiao)輸(shu)出脈沖波形不(bu)正常(chang)(chang)，Q1的(de)開(kai)關損耗和發熱量大(da)增，導致Q1過(guo)熱燒毀。高壓(ya)(ya)故(gu)障的(de)其(qi)他現象有(you)指示燈(deng)閃爍(shuo)，輸(shu)出電(dian)壓(ya)(ya)偏低(di)且(qie)不(bu)穩定，一般(ban)是(shi)(shi)T1的(de)引(yin)腳(jiao)有(you)虛焊(han)(han),或者D3,R12開(kai)路(lu),TL3842及其(qi)外圍電(dian)路(lu)無工(gong)作電(dian)源。

另(ling)有一(yi)種(zhong)罕見(jian)的高(gao)壓(ya)(ya)故(gu)障(zhang)是(shi)輸(shu)(shu)出(chu)電(dian)壓(ya)(ya)偏(pian)高(gao)到120V以上，一(yi)般是(shi)U2失效(xiao)，R13開路(lu)所致或U3擊穿(chuan)使(shi)U1的2腳(jiao)(jiao)電(dian)壓(ya)(ya)拉低，6腳(jiao)(jiao)送出(chu)超寬脈沖。此(ci)時不能長時間(jian)通電(dian)，否則將嚴重(zhong)燒毀低壓(ya)(ya)電(dian)路(lu)。低壓(ya)(ya)故(gu)障(zhang)大部(bu)分是(shi)充(chong)(chong)電(dian)器與(yu)電(dian)池正負極接反，導(dao)致R27燒斷，LM358擊穿(chuan)。其現象是(shi)紅燈一(yi)直亮，綠燈不亮，輸(shu)(shu)出(chu)電(dian)壓(ya)(ya)低，或者(zhe)輸(shu)(shu)出(chu)電(dian)壓(ya)(ya)接近(jin)0V，更換以上元件即可修(xiu)復。另(ling)外W2因抖動，輸(shu)(shu)出(chu)電(dian)壓(ya)(ya)漂移(yi)，若輸(shu)(shu)出(chu)電(dian)壓(ya)(ya)偏(pian)高(gao)，電(dian)池會過充(chong)(chong)，嚴重(zhong)失水，發燙，最終導(dao)致熱失控，充(chong)(chong)爆電(dian)池。

若(ruo)輸出(chu)電(dian)(dian)(dian)(dian)(dian)壓偏低(di)，會導致電(dian)(dian)(dian)(dian)(dian)池欠充(chong)(chong)(chong)(chong)。高低(di)壓電(dian)(dian)(dian)(dian)(dian)路(lu)均有(you)(you)故障(zhang)時，通電(dian)(dian)(dian)(dian)(dian)前應首(shou)先全面(mian)檢測所有(you)(you)的(de)二(er)極(ji)管(guan)(guan)(guan)(guan)，三(san)極(ji)管(guan)(guan)(guan)(guan)，光(guang)耦合器(qi)(qi)4N35，場(chang)效(xiao)應管(guan)(guan)(guan)(guan)，電(dian)(dian)(dian)(dian)(dian)解電(dian)(dian)(dian)(dian)(dian)容，集成電(dian)(dian)(dian)(dian)(dian)路(lu)，R25,R5,R12,R27，尤(you)其(qi)是D4（16A60V,快恢復(fu)二(er)極(ji)管(guan)(guan)(guan)(guan)），C10(63V,470UF)。避免盲目通電(dian)(dian)(dian)(dian)(dian)使故障(zhang)范圍進一(yi)步擴(kuo)大。有(you)(you)一(yi)部分充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)器(qi)(qi)輸出(chu)端(duan)具有(you)(you)防反接(jie)，防短(duan)路(lu)等特殊(shu)功能。其(qi)實就(jiu)是輸出(chu)端(duan)多加一(yi)個繼(ji)電(dian)(dian)(dian)(dian)(dian)器(qi)(qi)，在反接(jie)，短(duan)路(lu)的(de)情況下繼(ji)電(dian)(dian)(dian)(dian)(dian)器(qi)(qi)不工(gong)作(zuo)，充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)器(qi)(qi)無電(dian)(dian)(dian)(dian)(dian)壓輸出(chu)。還有(you)(you)一(yi)部分充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)器(qi)(qi)也具有(you)(you)防反接(jie)，防短(duan)路(lu)的(de)功能，其(qi)原理與前面(mian)介紹(shao)的(de)不同，其(qi)低(di)壓電(dian)(dian)(dian)(dian)(dian)路(lu)的(de)啟動電(dian)(dian)(dian)(dian)(dian)壓由被充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)池提(ti)供，且接(jie)有(you)(you)一(yi)個二(er)極(ji)管(guan)(guan)(guan)(guan)（防反接(jie)）。待電(dian)(dian)(dian)(dian)(dian)源正常啟動后，就(jiu)由充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)器(qi)(qi)提(ti)供低(di)壓工(gong)作(zuo)電(dian)(dian)(dian)(dian)(dian)源。