眾所周知，日(ri)常生活中(zhong)我們使用功(gong)放(fang)機(ji)，時間久了之后可能(neng)就會(hui)出現(xian)各(ge)種各(ge)樣(yang)的(de)問題(ti)，那(nei)么，功(gong)放(fang)機(ji)出現(xian)問題(ti)的(de)情況下應(ying)該(gai)怎么解(jie)(jie)(jie)決(jue)(jue)呢？隔(ge)山如隔(ge)行，雖然(ran)不(bu)是所有的(de)人都(dou)能(neng)解(jie)(jie)(jie)決(jue)(jue)的(de)，但(dan)是了解(jie)(jie)(jie)一些相關方面的(de)知識(shi)會(hui)使你(ni)迎(ying)刃而解(jie)(jie)(jie)。下面介紹功(gong)放(fang)機(ji)的(de)三種常見故障及維修方法。

一(yi)、整(zheng)機不工作

整機不(bu)工作(zuo)的(de)故障表現為通(tong)電后放大器無(wu)任何顯(xian)示，各(ge)功能鍵均失(shi)效，也(ye)無(wu)任何聲音，像未通(tong)電時(shi)一樣。

檢(jian)修時首先應(ying)檢(jian)查電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)。可用萬(wan)用表測(ce)量電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)插(cha)頭兩端的(de)直流電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)值(zhi)(電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)開(kai)關應(ying)接(jie)通(tong))，正常時應(ying)有數百歐姆的(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)值(zhi)。若(ruo)測(ce)得阻(zu)值(zhi)偏小(xiao)許多，且電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)變(bian)(bian)壓(ya)器嚴重發熱，說明電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)變(bian)(bian)壓(ya)器的(de)初級回(hui)路(lu)有局部(bu)(bu)短路(lu)處；若(ruo)測(ce)得阻(zu)值(zhi)為大，應(ying)檢(jian)查保險絲是否(fou)熔斷、變(bian)(bian)壓(ya)器初級繞組是否(fou)開(kai)路(lu)、電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)線與插(cha)頭之間有無斷線。有的(de)機器增加了溫度(du)保護(hu)裝置，在(zai)(zai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)變(bian)(bian)壓(ya)器的(de)初級回(hui)路(lu)中(zhong)接(jie)人了電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流保險絲(通(tong)常安(an)裝在(zai)(zai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)變(bian)(bian)壓(ya)器內部(bu)(bu)，將(jiang)變(bian)(bian)壓(ya)器外部(bu)(bu)的(de)絕緣紙去掉即可見到(dao))，它損壞后(hou)也會(hui)使電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)變(bian)(bian)壓(ya)器初級回(hui)路(lu)開(kai)路(lu)。

國產精品免費一區二區三區四區: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(sheng)大(da)

放大器的噪聲(sheng)有交流聲(sheng)、爆(bao)裂聲(sheng)、感(gan)應噪聲(sheng)和白噪聲(sheng)等。

檢修時，應(ying)先判斷噪(zao)聲(sheng)來(lai)自于前級還(huan)是(shi)(shi)來(lai)自于后(hou)(hou)級電(dian)路(lu)(lu)(lu)。可把(ba)前、后(hou)(hou)級的(de)信號連接插頭取下，若(ruo)噪(zao)聲(sheng)明(ming)顯變小，說明(ming)故(gu)障(zhang)在前級電(dian)路(lu)(lu)(lu)；反之，故(gu)障(zhang)在后(hou)(hou)級電(dian)路(lu)(lu)(lu)。交流(liu)(liu)聲(sheng)是(shi)(shi)指聽感低(di)(di)沉、單調而穩定(ding)的(de)100Hz交流(liu)(liu)哼(heng)聲(sheng)，主(zhu)要是(shi)(shi)電(dian)源部(bu)分濾波(bo)不良所(suo)致(zhi)，應(ying)著重(zhong)檢查電(dian)源整流(liu)(liu)、濾波(bo)和(he)穩壓元(yuan)件有無損壞。前、后(hou)(hou)級放大電(dian)路(lu)(lu)(lu)電(dian)源端的(de)退耦電(dian)容虛(xu)焊或失效，也會產生(sheng)一種類似交流(liu)(liu)聲(sheng)的(de)低(di)(di)頻(pin)振蕩噪(zao)聲(sheng)。

感應(ying)(ying)噪聲(sheng)是(shi)成(cheng)分較復雜且刺(ci)耳的(de)(de)交(jiao)流(liu)聲(sheng)，主(zhu)要(yao)是(shi)前(qian)級(ji)電(dian)(dian)路中的(de)(de)轉(zhuan)換開關(guan)、電(dian)(dian)位器(qi)接地不(bu)良(liang)(liang)或信號(hao)連(lian)線屏蔽不(bu)良(liang)(liang)所致。爆(bao)裂聲(sheng)是(shi)指間(jian)斷的(de)(de)“劈啪”、“咔(ka)咔(ka)”聲(sheng)，在前(qian)級(ji)電(dian)(dian)路中，應(ying)(ying)檢查信號(hao)輸(shu)(shu)入(ru)插(cha)頭與插(cha)座、轉(zhuan)換開關(guan)、電(dian)(dian)位器(qi)等是(shi)否接觸(chu)(chu)不(bu)良(liang)(liang)，耦合(he)電(dian)(dian)容有無(wu)虛焊、漏電(dian)(dian)等。后級(ji)放(fang)大(da)電(dian)(dian)路應(ying)(ying)檢查繼電(dian)(dian)器(qi)觸(chu)(chu)點(dian)是(shi)否氧化、輸(shu)(shu) 入(ru)耦合(he)電(dian)(dian)容有無(wu)漏電(dian)(dian)或接觸(chu)(chu)不(bu)良(liang)(liang)。另(ling)外，后級(ji)電(dian)(dian)路中的(de)(de)差分輸(shu)(shu)入(ru)管或恒流(liu)管軟(ruan)擊(ji)穿，也會產(chan)生類似電(dian)(dian)火花(hua)的(de)(de)“咔(ka)咔(ka)”噪聲(sheng)。白(bai)噪聲(sheng)是(shi)指無(wu)規(gui)則的(de)(de)連(lian)續“沙沙”聲(sheng)，通常(chang)是(shi)由前(qian)、后級(ji)放(fang)大(da)電(dian)(dian)路中的(de)(de)輸(shu)(shu)入(ru)級(ji)晶(jing)體管、場效應(ying)(ying)管或運放(fang)集成(cheng)電(dian)(dian)路的(de)(de)性能不(bu)良(liang)(liang)產(chan)生的(de)(de)本(ben)底噪聲(sheng)，檢修時(shi)，可用同(tong)規(gui)格的(de)(de)元件代換試之。

三、音(yin)量輕

專業國產精品免費一區二區三區四區: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(bu)分均正常，應判斷出(chu)(chu)故(gu)障(zhang)是(shi)在(zai)前(qian)級(ji)還(huan)是(shi)在(zai)后級(ji)電路。對于某一個聲(sheng)(sheng)道音(yin)輕(qing)(qing)，可將其(qi)前(qian)級(ji)電路輸(shu)出(chu)(chu)的(de)(de)信號交換輸(shu)入到(dao)另一聲(sheng)(sheng)道的(de)(de)后級(ji)電路，若音(yin)箱的(de)(de)聲(sheng)(sheng)音(yin)大(da)(da)小(xiao)不變，則故(gu)障(zhang)在(zai)后級(ji)電路；反之，故(gu)障(zhang)在(zai)前(qian)級(ji)電路。后級(ji)放大(da)(da)電路造(zao)成(cheng)的(de)(de)音(yin)輕(qing)(qing)，主要有輸(shu)出(chu)(chu)功(gong)率(lv)不足和增益(yi)不夠兩(liang)種(zhong)原因(yin)。可用適當(dang)加(jia)大(da)(da)輸(shu)入信號(例如將收錄機輸(shu)出(chu)(chu)給揚聲(sheng)(sheng)器的(de)(de)信號直接加(jia)至后級(ji)功(gong)放電路的(de)(de)輸(shu)入端，改變收錄機的(de)(de)音(yin)量(liang)，觀察功(gong)放輸(shu)出(chu)(chu)的(de)(de)變化)的(de)(de)方(fang)法來(lai)判斷是(shi)哪種(zhong)原因(yin)引起的(de)(de)。

若加大(da)(da)(da)輸入信號(hao)(hao)后(hou)，輸出的(de)(de)聲音(yin)足(zu)夠(gou)大(da)(da)(da)，說(shuo)明功(gong)放(fang)(fang)輸出功(gong)率(lv)足(zu)夠(gou)，只是增(zeng)益降低(di)(di)，應著(zhu)(zhu)重檢(jian)查(cha)(cha)繼電(dian)(dian)(dian)(dian)(dian)(dian)器(qi)觸點有無(wu)接觸電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)增(zeng)大(da)(da)(da)、輸入耦合(he)電(dian)(dian)(dian)(dian)(dian)(dian)容容量(liang)減小(xiao)、隔離電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)阻(zu)(zu)值增(zeng)大(da)(da)(da)、負(fu)反(fan)饋電(dian)(dian)(dian)(dian)(dian)(dian)容容量(liang)變小(xiao)或開(kai)路(lu)、負(fu)反(fan)饋電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)阻(zu)(zu)值增(zeng)大(da)(da)(da)或開(kai)路(lu)等現象。若加大(da)(da)(da)輸入信號(hao)(hao)后(hou)，輸出的(de)(de)聲音(yin)出現失(shi)真，音(yin)量(liang)并無(wu)顯著(zhu)(zhu)增(zeng)大(da)(da)(da)，說(shuo)明后(hou)級放(fang)(fang)大(da)(da)(da)器(qi)的(de)(de)輸出功(gong)率(lv)不(bu)(bu)足(zu)，應先檢(jian)查(cha)(cha)放(fang)(fang)大(da)(da)(da)器(qi)的(de)(de)正、負(fu)供電(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)壓是否(fou)偏低(di)(di)(若只是一(yi)個聲道(dao)音(yin)輕，可不(bu)(bu)必(bi)檢(jian)查(cha)(cha)電(dian)(dian)(dian)(dian)(dian)(dian)源供電(dian)(dian)(dian)(dian)(dian)(dian))、功(gong)率(lv)管或集成(cheng)(cheng)電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)的(de)(de)性能(neng)是否(fou)變差(cha)、發(fa)射(she)極電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)阻(zu)(zu)值有無(wu)變大(da)(da)(da)等。前級電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)中轉換開(kai)關、電(dian)(dian)(dian)(dian)(dian)(dian)位器(qi)所造(zao)成(cheng)(cheng)的(de)(de)音(yin)輕，采用直觀(guan)檢(jian)查(cha)(cha)較易發(fa)現，可對其進行(xing)清洗或更(geng)換。如懷疑某信號(hao)(hao)耦合(he)電(dian)(dian)(dian)(dian)(dian)(dian)容失(shi)效，可用同值電(dian)(dian)(dian)(dian)(dian)(dian)容并聯試之；放(fang)(fang)大(da)(da)(da)管或運放(fang)(fang)集成(cheng)(cheng)電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)性能(neng)不(bu)(bu)良，也可用代換法(fa)檢(jian)查(cha)(cha)。另外，負(fu)反(fan)饋元(yuan)件有問題，也會造(zao)成(cheng)(cheng)電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)增(zeng)益下(xia)降。