眾所周知(zhi)，日常生活(huo)中我們(men)使用功(gong)(gong)放機(ji)，時間(jian)久了之后可能就(jiu)會出(chu)現各種(zhong)各樣的(de)(de)(de)問題，那么，功(gong)(gong)放機(ji)出(chu)現問題的(de)(de)(de)情(qing)況(kuang)下應(ying)該怎么解(jie)決呢(ni)？隔(ge)山如(ru)隔(ge)行(xing)，雖然(ran)不是所有(you)的(de)(de)(de)人都能解(jie)決的(de)(de)(de)，但是了解(jie)一些相(xiang)關方面(mian)的(de)(de)(de)知(zhi)識會使你迎(ying)刃而解(jie)。下面(mian)介紹功(gong)(gong)放機(ji)的(de)(de)(de)三種(zhong)常見故障及維修方法。

一、整機(ji)不工作(zuo)

整機(ji)不工作的故(gu)障表現為通電(dian)后放大器無任何顯示，各功能(neng)鍵均(jun)失效，也無任何聲音，像(xiang)未(wei)通電(dian)時(shi)一樣。

檢修(xiu)時首(shou)先應(ying)檢查電源(yuan)電路。可(ke)用萬用表測量(liang)電源(yuan)插頭兩端的直流(liu)電阻(zu)(zu)值(電源(yuan)開(kai)(kai)關應(ying)接通)，正常時應(ying)有(you)(you)數百歐姆的電阻(zu)(zu)值。若(ruo)測得(de)阻(zu)(zu)值偏小許多，且電源(yuan)變(bian)壓器(qi)(qi)(qi)嚴重發熱，說明電源(yuan)變(bian)壓器(qi)(qi)(qi)的初(chu)(chu)級回(hui)路有(you)(you)局部短路處；若(ruo)測得(de)阻(zu)(zu)值為大，應(ying)檢查保險絲(si)是否(fou)(fou)熔斷、變(bian)壓器(qi)(qi)(qi)初(chu)(chu)級繞組是否(fou)(fou)開(kai)(kai)路、電源(yuan)線(xian)與插頭之間有(you)(you)無斷線(xian)。有(you)(you)的機器(qi)(qi)(qi)增加了溫度保護裝置，在電源(yuan)變(bian)壓器(qi)(qi)(qi)的初(chu)(chu)級回(hui)路中接人了電流(liu)保險絲(si)(通常安裝在電源(yuan)變(bian)壓器(qi)(qi)(qi)內部，將變(bian)壓器(qi)(qi)(qi)外部的絕緣紙去掉(diao)即可(ke)見到(dao))，它損壞后也會使(shi)電源(yuan)變(bian)壓器(qi)(qi)(qi)初(chu)(chu)級回(hui)路開(kai)(kai)路。

國產精品影視:重慶音響工程公司稱若電源插頭兩端阻值正常，可通電測量電源電路各輸出電壓是否正常。對于采用系統控制微處理器或邏輯控制電路的放大器，應著重檢查該控制電路的供電電壓(通常為+5V)是否正常。如無+5V電壓，應測量三端穩壓集成電路7805的輸入端電壓是否正常，若輸入端電壓不正常，應檢查整流、濾波電路。若7805輸入端電壓正常，而輸出端無十5V電壓或電壓偏低，可斷開負載看+5V電壓能否恢復正常。若+5V電壓正常，則故障在負載電路；若+5V電壓仍不正常，則故障在7805本身。若系統控制電路的+5V供電電壓正常，應再檢查微處理器的時鐘及復位信號是否正常、鍵控與顯示驅動電路有無損壞。

二(er)、噪聲大

放(fang)大器(qi)的(de)噪(zao)聲(sheng)有交流(liu)聲(sheng)、爆(bao)裂聲(sheng)、感應噪(zao)聲(sheng)和白噪(zao)聲(sheng)等。

檢(jian)修(xiu)時，應(ying)先(xian)判斷噪聲(sheng)來(lai)自于前(qian)(qian)級(ji)(ji)還是(shi)來(lai)自于后級(ji)(ji)電路。可把前(qian)(qian)、后級(ji)(ji)的(de)信號(hao)連接插頭(tou)取下，若噪聲(sheng)明顯變(bian)小(xiao)，說(shuo)明故(gu)障在(zai)前(qian)(qian)級(ji)(ji)電路；反之，故(gu)障在(zai)后級(ji)(ji)電路。交(jiao)(jiao)流(liu)聲(sheng)是(shi)指(zhi)聽感(gan)低沉、單調而穩定的(de)100Hz交(jiao)(jiao)流(liu)哼聲(sheng)，主要是(shi)電源(yuan)部分(fen)濾(lv)波不良所致，應(ying)著(zhu)重檢(jian)查電源(yuan)整(zheng)流(liu)、濾(lv)波和(he)穩壓元件有無損壞。前(qian)(qian)、后級(ji)(ji)放大電路電源(yuan)端的(de)退(tui)耦(ou)電容虛(xu)焊或失效，也會產生一種類(lei)似(si)交(jiao)(jiao)流(liu)聲(sheng)的(de)低頻振蕩噪聲(sheng)。

感(gan)應(ying)(ying)噪(zao)(zao)聲(sheng)(sheng)是(shi)(shi)(shi)成(cheng)分(fen)(fen)較(jiao)復雜且刺(ci)耳(er)的(de)交流聲(sheng)(sheng)，主要是(shi)(shi)(shi)前級電(dian)(dian)(dian)路(lu)中的(de)轉(zhuan)換(huan)開關、電(dian)(dian)(dian)位器(qi)接(jie)地不(bu)良或(huo)(huo)信號連線(xian)屏蔽不(bu)良所致(zhi)。爆(bao)裂聲(sheng)(sheng)是(shi)(shi)(shi)指間斷(duan)的(de)“劈啪(pa)”、“咔(ka)(ka)咔(ka)(ka)”聲(sheng)(sheng)，在前級電(dian)(dian)(dian)路(lu)中，應(ying)(ying)檢查(cha)信號輸(shu)(shu)入(ru)插頭與插座、轉(zhuan)換(huan)開關、電(dian)(dian)(dian)位器(qi)等是(shi)(shi)(shi)否接(jie)觸不(bu)良，耦合電(dian)(dian)(dian)容(rong)有(you)無虛焊、漏(lou)電(dian)(dian)(dian)等。后級放(fang)大電(dian)(dian)(dian)路(lu)應(ying)(ying)檢查(cha)繼電(dian)(dian)(dian)器(qi)觸點(dian)是(shi)(shi)(shi)否氧化、輸(shu)(shu) 入(ru)耦合電(dian)(dian)(dian)容(rong)有(you)無漏(lou)電(dian)(dian)(dian)或(huo)(huo)接(jie)觸不(bu)良。另外，后級電(dian)(dian)(dian)路(lu)中的(de)差(cha)分(fen)(fen)輸(shu)(shu)入(ru)管或(huo)(huo)恒流管軟(ruan)擊(ji)穿，也(ye)會產生(sheng)(sheng)類似電(dian)(dian)(dian)火花的(de)“咔(ka)(ka)咔(ka)(ka)”噪(zao)(zao)聲(sheng)(sheng)。白(bai)噪(zao)(zao)聲(sheng)(sheng)是(shi)(shi)(shi)指無規則(ze)的(de)連續“沙(sha)沙(sha)”聲(sheng)(sheng)，通常是(shi)(shi)(shi)由前、后級放(fang)大電(dian)(dian)(dian)路(lu)中的(de)輸(shu)(shu)入(ru)級晶體(ti)管、場效(xiao)應(ying)(ying)管或(huo)(huo)運放(fang)集成(cheng)電(dian)(dian)(dian)路(lu)的(de)性(xing)能不(bu)良產生(sheng)(sheng)的(de)本底(di)噪(zao)(zao)聲(sheng)(sheng)，檢修(xiu)時，可(ke)用同(tong)規格的(de)元件代換(huan)試之(zhi)。

三、音量輕(qing)

專業國產精品影視:音響工程公司稱所謂音輕故障，是指音頻信號在放大傳輸過程中，因某個放大級放大量變化或在某個環節被衰減，使放大器的增益下降或輸出功率變小。檢修時，首先應檢查信號源和音箱是否正常，可用替換的辦法來檢查。然后檢查各類轉換開關和控制電位器，看音量能否變大。

若以上各部分均正常，應判斷(duan)出故(gu)障是(shi)在前(qian)級(ji)還是(shi)在后級(ji)電(dian)(dian)路(lu)。對于(yu)某(mou)一個(ge)聲(sheng)(sheng)道(dao)音(yin)輕(qing)，可(ke)將其前(qian)級(ji)電(dian)(dian)路(lu)輸(shu)出的(de)(de)(de)信號交換輸(shu)入到(dao)另一聲(sheng)(sheng)道(dao)的(de)(de)(de)后級(ji)電(dian)(dian)路(lu)，若音(yin)箱的(de)(de)(de)聲(sheng)(sheng)音(yin)大小不(bu)變，則故(gu)障在后級(ji)電(dian)(dian)路(lu)；反之，故(gu)障在前(qian)級(ji)電(dian)(dian)路(lu)。后級(ji)放(fang)(fang)大電(dian)(dian)路(lu)造成的(de)(de)(de)音(yin)輕(qing)，主要有輸(shu)出功率不(bu)足和增益(yi)不(bu)夠兩種原因。可(ke)用適當加(jia)大輸(shu)入信號(例如將收錄(lu)(lu)機輸(shu)出給揚(yang)聲(sheng)(sheng)器的(de)(de)(de)信號直接加(jia)至(zhi)后級(ji)功放(fang)(fang)電(dian)(dian)路(lu)的(de)(de)(de)輸(shu)入端，改(gai)變收錄(lu)(lu)機的(de)(de)(de)音(yin)量，觀(guan)察功放(fang)(fang)輸(shu)出的(de)(de)(de)變化)的(de)(de)(de)方法(fa)來(lai)判斷(duan)是(shi)哪種原因引起的(de)(de)(de)。

若加大(da)(da)(da)(da)輸(shu)(shu)(shu)入(ru)信號(hao)后(hou)，輸(shu)(shu)(shu)出的(de)(de)(de)聲音足(zu)夠大(da)(da)(da)(da)，說(shuo)明(ming)功放輸(shu)(shu)(shu)出功率足(zu)夠，只(zhi)是增益降低(di)，應著重(zhong)檢(jian)查(cha)繼電(dian)(dian)(dian)(dian)(dian)(dian)器觸點有無接(jie)觸電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)增大(da)(da)(da)(da)、輸(shu)(shu)(shu)入(ru)耦(ou)合電(dian)(dian)(dian)(dian)(dian)(dian)容(rong)容(rong)量(liang)(liang)減小、隔離電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)阻(zu)(zu)值增大(da)(da)(da)(da)、負(fu)(fu)反饋(kui)電(dian)(dian)(dian)(dian)(dian)(dian)容(rong)容(rong)量(liang)(liang)變(bian)小或(huo)開路(lu)(lu)(lu)、負(fu)(fu)反饋(kui)電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)阻(zu)(zu)值增大(da)(da)(da)(da)或(huo)開路(lu)(lu)(lu)等現(xian)象。若加大(da)(da)(da)(da)輸(shu)(shu)(shu)入(ru)信號(hao)后(hou)，輸(shu)(shu)(shu)出的(de)(de)(de)聲音出現(xian)失真，音量(liang)(liang)并無顯著增大(da)(da)(da)(da)，說(shuo)明(ming)后(hou)級放大(da)(da)(da)(da)器的(de)(de)(de)輸(shu)(shu)(shu)出功率不(bu)足(zu)，應先檢(jian)查(cha)放大(da)(da)(da)(da)器的(de)(de)(de)正、負(fu)(fu)供電(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)壓是否(fou)偏低(di)(若只(zhi)是一個(ge)聲道音輕，可不(bu)必檢(jian)查(cha)電(dian)(dian)(dian)(dian)(dian)(dian)源供電(dian)(dian)(dian)(dian)(dian)(dian))、功率管(guan)或(huo)集成(cheng)電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)的(de)(de)(de)性能是否(fou)變(bian)差、發(fa)射極電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)阻(zu)(zu)值有無變(bian)大(da)(da)(da)(da)等。前級電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)中轉換(huan)開關、電(dian)(dian)(dian)(dian)(dian)(dian)位器所造(zao)(zao)成(cheng)的(de)(de)(de)音輕，采用直(zhi)觀檢(jian)查(cha)較易發(fa)現(xian)，可對其進(jin)行(xing)清洗或(huo)更(geng)換(huan)。如懷疑某信號(hao)耦(ou)合電(dian)(dian)(dian)(dian)(dian)(dian)容(rong)失效，可用同值電(dian)(dian)(dian)(dian)(dian)(dian)容(rong)并聯試之；放大(da)(da)(da)(da)管(guan)或(huo)運(yun)放集成(cheng)電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)性能不(bu)良，也(ye)(ye)可用代換(huan)法檢(jian)查(cha)。另(ling)外，負(fu)(fu)反饋(kui)元件(jian)有問題，也(ye)(ye)會造(zao)(zao)成(cheng)電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)增益下降。