眾所周知，日常生活中我們使用功放機(ji)，時間(jian)久了之后可(ke)能就會出現(xian)各(ge)種(zhong)各(ge)樣的(de)問(wen)題，那么(me)，功放機(ji)出現(xian)問(wen)題的(de)情況下(xia)應該怎么(me)解(jie)決呢？隔(ge)山如隔(ge)行，雖然不是(shi)(shi)所有的(de)人(ren)都能解(jie)決的(de)，但是(shi)(shi)了解(jie)一些相關方面的(de)知識會使你迎刃(ren)而解(jie)。下(xia)面介紹功放機(ji)的(de)三種(zhong)常見故障及維修方法(fa)。

一、整機不工作

整機不工作的故(gu)障表現為通電(dian)后放(fang)大(da)器無任(ren)(ren)何顯示，各(ge)功(gong)能(neng)鍵均失效，也無任(ren)(ren)何聲音，像未通電(dian)時一樣。

檢修時(shi)首先應檢查(cha)電(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)電(dian)(dian)(dian)路(lu)。可用萬用表(biao)測量(liang)電(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)插頭兩端的(de)直(zhi)流(liu)電(dian)(dian)(dian)阻(zu)值(電(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)開(kai)關應接通)，正常(chang)時(shi)應有數百歐姆的(de)電(dian)(dian)(dian)阻(zu)值。若測得(de)阻(zu)值偏小許多，且電(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)變(bian)(bian)壓(ya)器嚴重發(fa)熱(re)，說明(ming)電(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)變(bian)(bian)壓(ya)器的(de)初級回(hui)(hui)路(lu)有局部短(duan)路(lu)處(chu)；若測得(de)阻(zu)值為大，應檢查(cha)保險絲是(shi)否熔(rong)斷(duan)(duan)、變(bian)(bian)壓(ya)器初級繞組是(shi)否開(kai)路(lu)、電(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)線(xian)與插頭之間有無(wu)斷(duan)(duan)線(xian)。有的(de)機器增加了(le)溫(wen)度(du)保護裝(zhuang)置，在(zai)電(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)變(bian)(bian)壓(ya)器的(de)初級回(hui)(hui)路(lu)中接人(ren)了(le)電(dian)(dian)(dian)流(liu)保險絲(通常(chang)安裝(zhuang)在(zai)電(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)變(bian)(bian)壓(ya)器內部，將(jiang)變(bian)(bian)壓(ya)器外(wai)部的(de)絕緣紙去掉(diao)即可見到)，它損壞(huai)后也會使電(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)變(bian)(bian)壓(ya)器初級回(hui)(hui)路(lu)開(kai)路(lu)。

中文字幕日韓歐美一區二區三區: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、噪聲大

放大(da)器的噪聲有交流(liu)聲、爆裂聲、感應噪聲和白噪聲等(deng)。

檢修(xiu)時，應(ying)先判斷噪(zao)聲(sheng)來(lai)自(zi)于前(qian)(qian)級(ji)還是來(lai)自(zi)于后(hou)級(ji)電(dian)(dian)路。可把前(qian)(qian)、后(hou)級(ji)的(de)信號連接插頭取下，若噪(zao)聲(sheng)明顯變(bian)小，說明故障在前(qian)(qian)級(ji)電(dian)(dian)路；反之(zhi)，故障在后(hou)級(ji)電(dian)(dian)路。交(jiao)流(liu)聲(sheng)是指聽感低(di)沉、單調而(er)穩定的(de)100Hz交(jiao)流(liu)哼聲(sheng)，主要是電(dian)(dian)源(yuan)(yuan)部(bu)分濾波不(bu)良所(suo)致，應(ying)著(zhu)重檢查電(dian)(dian)源(yuan)(yuan)整流(liu)、濾波和穩壓元件有無損壞。前(qian)(qian)、后(hou)級(ji)放大電(dian)(dian)路電(dian)(dian)源(yuan)(yuan)端的(de)退耦電(dian)(dian)容虛焊或失效，也會產生一種類似交(jiao)流(liu)聲(sheng)的(de)低(di)頻(pin)振(zhen)蕩噪(zao)聲(sheng)。

感(gan)應(ying)噪(zao)聲(sheng)(sheng)是(shi)(shi)(shi)成分較(jiao)復雜且(qie)刺耳的交流聲(sheng)(sheng)，主要是(shi)(shi)(shi)前(qian)級(ji)電(dian)(dian)路中(zhong)的轉換開(kai)關(guan)、電(dian)(dian)位(wei)器(qi)接地(di)不良或(huo)信(xin)(xin)號連線屏蔽不良所致。爆裂聲(sheng)(sheng)是(shi)(shi)(shi)指(zhi)間(jian)斷的“劈啪”、“咔咔”聲(sheng)(sheng)，在(zai)前(qian)級(ji)電(dian)(dian)路中(zhong)，應(ying)檢查信(xin)(xin)號輸入(ru)插頭與插座、轉換開(kai)關(guan)、電(dian)(dian)位(wei)器(qi)等是(shi)(shi)(shi)否(fou)接觸(chu)不良，耦合電(dian)(dian)容(rong)有(you)無(wu)虛(xu)焊、漏(lou)電(dian)(dian)等。后級(ji)放(fang)大電(dian)(dian)路應(ying)檢查繼電(dian)(dian)器(qi)觸(chu)點是(shi)(shi)(shi)否(fou)氧化、輸 入(ru)耦合電(dian)(dian)容(rong)有(you)無(wu)漏(lou)電(dian)(dian)或(huo)接觸(chu)不良。另外(wai)，后級(ji)電(dian)(dian)路中(zhong)的差(cha)分輸入(ru)管或(huo)恒流管軟(ruan)擊穿，也(ye)會(hui)產生類似電(dian)(dian)火花的“咔咔”噪(zao)聲(sheng)(sheng)。白噪(zao)聲(sheng)(sheng)是(shi)(shi)(shi)指(zhi)無(wu)規則的連續“沙沙”聲(sheng)(sheng)，通常是(shi)(shi)(shi)由前(qian)、后級(ji)放(fang)大電(dian)(dian)路中(zhong)的輸入(ru)級(ji)晶(jing)體管、場效應(ying)管或(huo)運放(fang)集成電(dian)(dian)路的性能不良產生的本底噪(zao)聲(sheng)(sheng)，檢修(xiu)時，可用(yong)同(tong)規格的元件代換試之。

三、音量輕

專業中文字幕日韓歐美一區二區三區: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(yi)上各部分均正常，應(ying)判斷出(chu)(chu)(chu)故障(zhang)是(shi)(shi)在前級(ji)(ji)還是(shi)(shi)在后(hou)級(ji)(ji)電(dian)(dian)路(lu)(lu)。對于某(mou)一(yi)個聲(sheng)(sheng)道(dao)音(yin)(yin)輕，可(ke)將其前級(ji)(ji)電(dian)(dian)路(lu)(lu)輸(shu)出(chu)(chu)(chu)的(de)(de)信(xin)號交(jiao)換輸(shu)入(ru)(ru)到另一(yi)聲(sheng)(sheng)道(dao)的(de)(de)后(hou)級(ji)(ji)電(dian)(dian)路(lu)(lu)，若音(yin)(yin)箱的(de)(de)聲(sheng)(sheng)音(yin)(yin)大(da)小(xiao)不(bu)(bu)變，則故障(zhang)在后(hou)級(ji)(ji)電(dian)(dian)路(lu)(lu)；反之(zhi)，故障(zhang)在前級(ji)(ji)電(dian)(dian)路(lu)(lu)。后(hou)級(ji)(ji)放(fang)(fang)大(da)電(dian)(dian)路(lu)(lu)造成(cheng)的(de)(de)音(yin)(yin)輕，主要有輸(shu)出(chu)(chu)(chu)功率不(bu)(bu)足(zu)和增益(yi)不(bu)(bu)夠(gou)兩種原因(yin)。可(ke)用適當加(jia)大(da)輸(shu)入(ru)(ru)信(xin)號(例(li)如(ru)將收(shou)錄(lu)機(ji)輸(shu)出(chu)(chu)(chu)給揚聲(sheng)(sheng)器的(de)(de)信(xin)號直接加(jia)至后(hou)級(ji)(ji)功放(fang)(fang)電(dian)(dian)路(lu)(lu)的(de)(de)輸(shu)入(ru)(ru)端，改變收(shou)錄(lu)機(ji)的(de)(de)音(yin)(yin)量，觀察功放(fang)(fang)輸(shu)出(chu)(chu)(chu)的(de)(de)變化)的(de)(de)方法來判斷是(shi)(shi)哪種原因(yin)引(yin)起的(de)(de)。

若加大(da)(da)(da)輸(shu)(shu)(shu)入信(xin)(xin)號后(hou)，輸(shu)(shu)(shu)出的聲音(yin)足夠大(da)(da)(da)，說明功(gong)放(fang)輸(shu)(shu)(shu)出功(gong)率足夠，只(zhi)是增(zeng)益(yi)降低(di)，應著重(zhong)檢查(cha)(cha)(cha)繼電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)器觸點有(you)無(wu)接觸電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻增(zeng)大(da)(da)(da)、輸(shu)(shu)(shu)入耦合電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)容容量減(jian)小(xiao)、隔離電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻阻值增(zeng)大(da)(da)(da)、負反(fan)饋(kui)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)容容量變(bian)小(xiao)或開(kai)路、負反(fan)饋(kui)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻阻值增(zeng)大(da)(da)(da)或開(kai)路等現象。若加大(da)(da)(da)輸(shu)(shu)(shu)入信(xin)(xin)號后(hou)，輸(shu)(shu)(shu)出的聲音(yin)出現失真，音(yin)量并無(wu)顯著增(zeng)大(da)(da)(da)，說明后(hou)級(ji)放(fang)大(da)(da)(da)器的輸(shu)(shu)(shu)出功(gong)率不足，應先檢查(cha)(cha)(cha)放(fang)大(da)(da)(da)器的正、負供電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓是否偏(pian)低(di)(若只(zhi)是一(yi)個(ge)聲道音(yin)輕(qing)，可(ke)不必檢查(cha)(cha)(cha)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源供電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian))、功(gong)率管或集成(cheng)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路的性(xing)(xing)能(neng)是否變(bian)差、發射極(ji)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻阻值有(you)無(wu)變(bian)大(da)(da)(da)等。前(qian)級(ji)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路中轉(zhuan)換(huan)開(kai)關、電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)位器所造成(cheng)的音(yin)輕(qing)，采用(yong)直觀檢查(cha)(cha)(cha)較(jiao)易(yi)發現，可(ke)對其進行(xing)清洗或更換(huan)。如懷疑某(mou)信(xin)(xin)號耦合電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)容失效(xiao)，可(ke)用(yong)同(tong)值電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)容并聯試之；放(fang)大(da)(da)(da)管或運放(fang)集成(cheng)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路性(xing)(xing)能(neng)不良，也可(ke)用(yong)代換(huan)法檢查(cha)(cha)(cha)。另外(wai)，負反(fan)饋(kui)元件有(you)問題(ti)，也會造成(cheng)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路增(zeng)益(yi)下(xia)降。