眾所周知，日(ri)常生(sheng)活中(zhong)我們(men)使用功放機(ji)，時間(jian)久了之后(hou)可能就會出現各(ge)種各(ge)樣的(de)問題，那么(me)，功放機(ji)出現問題的(de)情況下應(ying)該怎(zen)么(me)解(jie)決呢？隔(ge)山如隔(ge)行，雖然不是(shi)所有的(de)人(ren)都能解(jie)決的(de)，但(dan)是(shi)了解(jie)一(yi)些相關方(fang)面的(de)知識會使你迎刃(ren)而解(jie)。下面介紹(shao)功放機(ji)的(de)三(san)種常見故障及維修(xiu)方(fang)法。

一(yi)、整機不工作

整機不工作的故障表現為通(tong)電后放大器無任(ren)何顯示，各功能(neng)鍵均失(shi)效，也(ye)無任(ren)何聲音，像未通(tong)電時一樣。

檢(jian)修時首先應(ying)檢(jian)查電(dian)(dian)(dian)(dian)源(yuan)(yuan)電(dian)(dian)(dian)(dian)路(lu)(lu)。可用萬用表測量(liang)電(dian)(dian)(dian)(dian)源(yuan)(yuan)插頭兩端的(de)(de)直流(liu)電(dian)(dian)(dian)(dian)阻(zu)(zu)值(zhi)(zhi)(電(dian)(dian)(dian)(dian)源(yuan)(yuan)開(kai)關應(ying)接(jie)通)，正常時應(ying)有(you)數百歐(ou)姆的(de)(de)電(dian)(dian)(dian)(dian)阻(zu)(zu)值(zhi)(zhi)。若(ruo)測得阻(zu)(zu)值(zhi)(zhi)偏(pian)小許多(duo)，且(qie)電(dian)(dian)(dian)(dian)源(yuan)(yuan)變(bian)壓(ya)(ya)(ya)器(qi)嚴重發熱，說明(ming)電(dian)(dian)(dian)(dian)源(yuan)(yuan)變(bian)壓(ya)(ya)(ya)器(qi)的(de)(de)初(chu)級回(hui)路(lu)(lu)有(you)局部(bu)短路(lu)(lu)處；若(ruo)測得阻(zu)(zu)值(zhi)(zhi)為大(da)，應(ying)檢(jian)查保險絲(si)是(shi)否熔斷、變(bian)壓(ya)(ya)(ya)器(qi)初(chu)級繞(rao)組是(shi)否開(kai)路(lu)(lu)、電(dian)(dian)(dian)(dian)源(yuan)(yuan)線與插頭之間有(you)無斷線。有(you)的(de)(de)機器(qi)增加了(le)溫度保護裝(zhuang)(zhuang)置(zhi)，在電(dian)(dian)(dian)(dian)源(yuan)(yuan)變(bian)壓(ya)(ya)(ya)器(qi)的(de)(de)初(chu)級回(hui)路(lu)(lu)中接(jie)人了(le)電(dian)(dian)(dian)(dian)流(liu)保險絲(si)(通常安裝(zhuang)(zhuang)在電(dian)(dian)(dian)(dian)源(yuan)(yuan)變(bian)壓(ya)(ya)(ya)器(qi)內部(bu)，將變(bian)壓(ya)(ya)(ya)器(qi)外部(bu)的(de)(de)絕緣紙去掉即(ji)可見(jian)到)，它損壞后也會(hui)使電(dian)(dian)(dian)(dian)源(yuan)(yuan)變(bian)壓(ya)(ya)(ya)器(qi)初(chu)級回(hui)路(lu)(lu)開(kai)路(lu)(lu)。

四虎亞洲一區: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、噪(zao)聲大

放大器的(de)噪(zao)(zao)聲(sheng)有交流聲(sheng)、爆裂聲(sheng)、感應噪(zao)(zao)聲(sheng)和白(bai)噪(zao)(zao)聲(sheng)等(deng)。

檢(jian)修(xiu)時(shi)，應先判斷噪(zao)聲來(lai)自(zi)于前(qian)級還(huan)是(shi)來(lai)自(zi)于后級電路。可把前(qian)、后級的信號連接插頭取下，若噪(zao)聲明顯(xian)變小，說(shuo)明故(gu)(gu)障在前(qian)級電路；反之，故(gu)(gu)障在后級電路。交(jiao)流(liu)聲是(shi)指聽感低(di)沉、單調而穩定的100Hz交(jiao)流(liu)哼聲，主要(yao)是(shi)電源(yuan)部(bu)分濾(lv)波(bo)不良所致(zhi)，應著重檢(jian)查電源(yuan)整流(liu)、濾(lv)波(bo)和穩壓元件有無(wu)損壞。前(qian)、后級放大電路電源(yuan)端的退耦電容虛焊或(huo)失效，也會產生一種類似交(jiao)流(liu)聲的低(di)頻(pin)振蕩噪(zao)聲。

感應(ying)噪聲(sheng)是(shi)成分較復雜且刺耳的(de)(de)(de)交流(liu)聲(sheng)，主要是(shi)前級(ji)電(dian)(dian)(dian)路(lu)中的(de)(de)(de)轉換開關、電(dian)(dian)(dian)位器接地(di)不(bu)良(liang)或(huo)信號(hao)連(lian)線屏蔽不(bu)良(liang)所(suo)致。爆(bao)裂(lie)聲(sheng)是(shi)指(zhi)間斷(duan)的(de)(de)(de)“劈啪(pa)”、“咔(ka)咔(ka)”聲(sheng)，在前級(ji)電(dian)(dian)(dian)路(lu)中，應(ying)檢(jian)(jian)查(cha)(cha)信號(hao)輸(shu)(shu)入(ru)插(cha)頭與(yu)插(cha)座(zuo)、轉換開關、電(dian)(dian)(dian)位器等(deng)是(shi)否(fou)接觸不(bu)良(liang)，耦合電(dian)(dian)(dian)容有無虛焊(han)、漏電(dian)(dian)(dian)等(deng)。后(hou)級(ji)放(fang)大(da)電(dian)(dian)(dian)路(lu)應(ying)檢(jian)(jian)查(cha)(cha)繼(ji)電(dian)(dian)(dian)器觸點(dian)是(shi)否(fou)氧化、輸(shu)(shu) 入(ru)耦合電(dian)(dian)(dian)容有無漏電(dian)(dian)(dian)或(huo)接觸不(bu)良(liang)。另外，后(hou)級(ji)電(dian)(dian)(dian)路(lu)中的(de)(de)(de)差分輸(shu)(shu)入(ru)管(guan)或(huo)恒流(liu)管(guan)軟擊穿，也會產(chan)生(sheng)類似電(dian)(dian)(dian)火花的(de)(de)(de)“咔(ka)咔(ka)”噪聲(sheng)。白噪聲(sheng)是(shi)指(zhi)無規則的(de)(de)(de)連(lian)續(xu)“沙(sha)沙(sha)”聲(sheng)，通常是(shi)由前、后(hou)級(ji)放(fang)大(da)電(dian)(dian)(dian)路(lu)中的(de)(de)(de)輸(shu)(shu)入(ru)級(ji)晶體管(guan)、場效應(ying)管(guan)或(huo)運(yun)放(fang)集(ji)成電(dian)(dian)(dian)路(lu)的(de)(de)(de)性能不(bu)良(liang)產(chan)生(sheng)的(de)(de)(de)本底噪聲(sheng)，檢(jian)(jian)修時，可用同規格的(de)(de)(de)元件(jian)代(dai)換試之。

三、音量輕

專業四虎亞洲一區: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(bu)分均正常，應判(pan)(pan)斷(duan)出故障(zhang)是(shi)在前(qian)級(ji)還是(shi)在后(hou)級(ji)電路(lu)。對(dui)于某一個聲道音輕(qing)，可將(jiang)其(qi)前(qian)級(ji)電路(lu)輸(shu)出的(de)(de)信(xin)(xin)號(hao)交換輸(shu)入到(dao)另一聲道的(de)(de)后(hou)級(ji)電路(lu)，若音箱(xiang)的(de)(de)聲音大小不(bu)變(bian)(bian)，則(ze)故障(zhang)在后(hou)級(ji)電路(lu)；反之(zhi)，故障(zhang)在前(qian)級(ji)電路(lu)。后(hou)級(ji)放(fang)大電路(lu)造成的(de)(de)音輕(qing)，主要(yao)有輸(shu)出功(gong)率不(bu)足和增益不(bu)夠兩種原因(yin)。可用適當加(jia)大輸(shu)入信(xin)(xin)號(hao)(例如將(jiang)收錄機(ji)輸(shu)出給揚(yang)聲器的(de)(de)信(xin)(xin)號(hao)直(zhi)接加(jia)至后(hou)級(ji)功(gong)放(fang)電路(lu)的(de)(de)輸(shu)入端(duan)，改變(bian)(bian)收錄機(ji)的(de)(de)音量，觀(guan)察(cha)功(gong)放(fang)輸(shu)出的(de)(de)變(bian)(bian)化(hua))的(de)(de)方法來判(pan)(pan)斷(duan)是(shi)哪種原因(yin)引起(qi)的(de)(de)。

若加(jia)大(da)(da)(da)(da)(da)輸(shu)(shu)入(ru)信號(hao)后(hou)，輸(shu)(shu)出(chu)(chu)(chu)(chu)的聲音(yin)足夠大(da)(da)(da)(da)(da)，說明功放輸(shu)(shu)出(chu)(chu)(chu)(chu)功率(lv)(lv)足夠，只是(shi)增(zeng)(zeng)益(yi)(yi)降低，應著重(zhong)檢查(cha)(cha)繼電(dian)(dian)(dian)(dian)器(qi)(qi)觸點有無(wu)(wu)接觸電(dian)(dian)(dian)(dian)阻(zu)(zu)增(zeng)(zeng)大(da)(da)(da)(da)(da)、輸(shu)(shu)入(ru)耦(ou)合(he)(he)電(dian)(dian)(dian)(dian)容(rong)(rong)容(rong)(rong)量(liang)減(jian)小(xiao)、隔離電(dian)(dian)(dian)(dian)阻(zu)(zu)阻(zu)(zu)值增(zeng)(zeng)大(da)(da)(da)(da)(da)、負反(fan)饋電(dian)(dian)(dian)(dian)容(rong)(rong)容(rong)(rong)量(liang)變(bian)小(xiao)或開路(lu)(lu)(lu)、負反(fan)饋電(dian)(dian)(dian)(dian)阻(zu)(zu)阻(zu)(zu)值增(zeng)(zeng)大(da)(da)(da)(da)(da)或開路(lu)(lu)(lu)等(deng)(deng)現(xian)象。若加(jia)大(da)(da)(da)(da)(da)輸(shu)(shu)入(ru)信號(hao)后(hou)，輸(shu)(shu)出(chu)(chu)(chu)(chu)的聲音(yin)出(chu)(chu)(chu)(chu)現(xian)失真，音(yin)量(liang)并(bing)無(wu)(wu)顯著增(zeng)(zeng)大(da)(da)(da)(da)(da)，說明后(hou)級放大(da)(da)(da)(da)(da)器(qi)(qi)的輸(shu)(shu)出(chu)(chu)(chu)(chu)功率(lv)(lv)不足，應先檢查(cha)(cha)放大(da)(da)(da)(da)(da)器(qi)(qi)的正、負供(gong)電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)壓(ya)是(shi)否偏低(若只是(shi)一個聲道音(yin)輕(qing)，可不必檢查(cha)(cha)電(dian)(dian)(dian)(dian)源供(gong)電(dian)(dian)(dian)(dian))、功率(lv)(lv)管或集成電(dian)(dian)(dian)(dian)路(lu)(lu)(lu)的性能是(shi)否變(bian)差、發射(she)極電(dian)(dian)(dian)(dian)阻(zu)(zu)阻(zu)(zu)值有無(wu)(wu)變(bian)大(da)(da)(da)(da)(da)等(deng)(deng)。前級電(dian)(dian)(dian)(dian)路(lu)(lu)(lu)中轉換(huan)(huan)開關、電(dian)(dian)(dian)(dian)位(wei)器(qi)(qi)所造成的音(yin)輕(qing)，采用(yong)直觀檢查(cha)(cha)較(jiao)易(yi)發現(xian)，可對其(qi)進行清洗或更換(huan)(huan)。如懷(huai)疑某(mou)信號(hao)耦(ou)合(he)(he)電(dian)(dian)(dian)(dian)容(rong)(rong)失效，可用(yong)同值電(dian)(dian)(dian)(dian)容(rong)(rong)并(bing)聯(lian)試(shi)之；放大(da)(da)(da)(da)(da)管或運(yun)放集成電(dian)(dian)(dian)(dian)路(lu)(lu)(lu)性能不良，也可用(yong)代換(huan)(huan)法檢查(cha)(cha)。另外，負反(fan)饋元件有問題，也會造成電(dian)(dian)(dian)(dian)路(lu)(lu)(lu)增(zeng)(zeng)益(yi)(yi)下降。