本文將對開關電(dian)源中(zhong)恒電(dian)流源電(dian)路的工(gong)作原理(li)及特點等進行分析，供(gong)讀者。

　　一、開關電源恒流源電路的(de)(de)(de)構成及工作(zuo)原(yuan)理由分(fen)立元件組(zu)(zu)成的(de)(de)(de)開(kai)(kai)關(guan)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)中的(de)(de)(de)恒(heng)流(liu)(liu)源(yuan)(yuan)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)由分(fen)立元件組(zu)(zu)成的(de)(de)(de)開(kai)(kai)關(guan)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)采(cai)用恒(heng)流(liu)(liu)源(yuan)(yuan)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)的(de)(de)(de)彩電(dian)(dian)(dian)(dian)(dian)(dian)(dian)有(you)：長虹NC-2、NC- 3、A6等(deng)機心系列闈電(dian)(dian)(dian)(dian)(dian)(dian)(dian)。另外，東芝2929DH/DXH彩3開(kai)(kai)關(guan)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)基(ji)(ji)本相同，也是采(cai)用恒(heng)流(liu)(liu)源(yuan)(yuan)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)揠(ya)。，是這種開(kai)(kai)關(guan)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)中的(de)(de)(de)振(zhen)(zhen)蕩(dang)和恒(heng)流(liu)(liu)源(yuan)(yuan)原(yuan)理圖。振(zhen)(zhen)蕩(dang)‘路(lu)由-⑨繞組(zu)(zu)是振(zhen)(zhen)蕩(dang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)的(de)(de)(de)反饋支路(lu)。恒(heng)流(liu)(liu)源(yuan)(yuan)由VQ820、R822、VD820、C821、R823、T803⑦~⑧和⑦⑨繞組(zu)(zu)構成。其(qi)工作(zuo)原(yuan)理是：在VQ83截(jie)(jie)止(zhi)期間，T803的(de)(de)(de)⑧端(duan)(duan)(duan)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)為正(zheng)，⑨端(duan)(duan)(duan)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)為負。⑨端(duan)(duan)(duan)的(de)(de)(de)負電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)經R823加(jia)到VQ820的(de)(de)(de)基(ji)(ji)極(ji)(ji)，使(shi)VQ820截(jie)(jie)止(zhi)。T803⑧端(duan)(duan)(duan)的(de)(de)(de)正(zheng)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)通(tong)過VD820向C821充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)，C821上(shang)充(chong)得的(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)就(jiu)成為VQ820導(dao)通(tong)時(shi)(shi)所需的(de)(de)(de)工作(zuo)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)。VQ83導(dao)通(tong)時(shi)(shi)，T803⑧端(duan)(duan)(duan)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)變(bian)負，⑨端(duan)(duan)(duan)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)由負變(bian)正(zheng)。⑧端(duan)(duan)(duan)的(de)(de)(de)負電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)加(jia)到VD820正(zheng)極(ji)(ji)使(shi)其(qi)截(jie)(jie)止(zhi)，⑨端(duan)(duan)(duan)的(de)(de)(de)正(zheng)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)經R823加(jia)到VQ820基(ji)(ji)極(ji)(ji)使(shi)其(qi)導(dao)通(tong)。VQ820導(dao)通(tong)后，流(liu)(liu)經VQ820集(ji)-射之(zhi)間的(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)便成為VQ83的(de)(de)(de)基(ji)(ji)極(ji)(ji)注(zhu)人電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)。VQ820的(de)(de)(de)導(dao)通(tong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)不(bu)受(shou)交流(liu)(liu)輸人電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)波(bo)動的(de)(de)(de)影響(xiang)，其(qi)大(da)(da)小取決于C821上(shang)的(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)和電(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻R822的(de)(de)(de)大(da)(da)小，所以，VQ83的(de)(de)(de)基(ji)(ji)極(ji)(ji)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)同樣不(bu)受(shou)交流(liu)(liu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)波(bo)動的(de)(de)(de)影響(xiang)，這就(jiu)展(zhan)寬了開(kai)(kai)關(guan)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)對交流(liu)(liu)輸入電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)的(de)(de)(de)適應(ying)范圍(wei)。

　　恒流(liu)源(yuan)電(dian)(dian)路(lu)(lu)6333等。采(cai)用(yong)STR-S6309組(zu)成開關電(dian)(dian)源(yuan)的(de)彩電(dian)(dian)有：康佳06系列），夏(xia)普25N42-E2、29FN1、29AW1及寬(kuan)屏W288、W328，熊貓C64P2、2919，長城G8173MF、G8263、G8363，創維CTV-8259、CTV-8298.厚膜電(dian)(dian)路(lu)(lu)STR-S6308與STR-S6309內部電(dian)(dian)路(lu)(lu)結構基本相同，恒流(liu)源(yuan)電(dian)(dian)路(lu)(lu)和(he)原(yuan)理完全相同。下面以STR-S6308厚膜電(dian)(dian)路(lu)(lu)組(zu)成的(de)開關電(dian)(dian)源(yuan)為例(li)說明其恒流(liu)源(yuan)工作原(yuan)理。

　　是(shi)STR-6308厚膜電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)組(zu)成的(de)(de)(de)開(kai)(kai)關(guan)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)中(zhong)的(de)(de)(de)振蕩和(he)恒流(liu)(liu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)原理圖(tu)。圖(tu)中(zhong)，IC801內(nei)部的(de)(de)(de)Q1是(shi)開(kai)(kai)關(guan)管，R803、R804是(shi)振蕩啟動電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)，C812、R807、T803①-②繞(rao)組(zu)是(shi)振蕩電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)的(de)(de)(de)反(fan)饋支(zhi)路(lu)。恒流(liu)(liu)源(yuan)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)由(you)IC801內(nei)部的(de)(de)(de)Q3、R2、R3、D2及外部的(de)(de)(de)C814、D803、R806和(he)T803①-②繞(rao)組(zu)構成。其(qi)(qi)恒流(liu)(liu)源(yuan)工作原理為(wei)(wei)(wei)：在（1截止期間，T803②端(duan)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)為(wei)(wei)(wei)正(zheng)(zheng)，①端(duan)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)為(wei)(wei)(wei)負(fu)。T803②端(duan)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)通(tong)(tong)過IC801內(nei)部的(de)(de)(de)D2向C814充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)，其(qi)(qi)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)路(lu)徑(jing)為(wei)(wei)(wei)：T803②④一(yi)814-803-803①。C814上充(chong)(chong)得的(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)就(jiu)成為(wei)(wei)(wei)Q3導(dao)通(tong)(tong)時(shi)所(suo)需要的(de)(de)(de)工作電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)。在Q1導(dao)通(tong)(tong)時(shi)，T803②端(duan)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)由(you)正(zheng)(zheng)變(bian)負(fu)，①端(duan)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)由(you)負(fu)變(bian)正(zheng)(zheng)。②端(duan)的(de)(de)(de)負(fu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)加到D2的(de)(de)(de)正(zheng)(zheng)極(ji)(ji)使其(qi)(qi)截止，①端(duan)的(de)(de)(de)正(zheng)(zheng)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)加到IC801的(de)(de)(de)⑤腳，再(zai)通(tong)(tong)過其(qi)(qi)內(nei)部R3加到Q3的(de)(de)(de)基極(ji)(ji)使其(qi)(qi)導(dao)通(tong)(tong)。Q3導(dao)通(tong)(tong)后，C814通(tong)(tong)過Q3放電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)，其(qi)(qi)放電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)路(lu)徑(jing)為(wei)(wei)(wei)：C814正(zheng)(zheng)極(ji)(ji)->IC801dH3ce極(ji)(ji)->Qlbe極(ji)(ji)―IC801②―R806->C814負(fu)極(ji)(ji)。Q3導(dao)通(tong)(tong)后，流(liu)(liu)過Q3集射之間的(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)便成為(wei)(wei)(wei)（1的(de)(de)(de)基極(ji)(ji)注人(ren)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)。因(yin)為(wei)(wei)(wei)Q3的(de)(de)(de)導(dao)通(tong)(tong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)不受(shou)交(jiao)(jiao)流(liu)(liu)輸人(ren)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)波動的(de)(de)(de)影響，只取決于C814上的(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)和(he)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)R806的(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)大(da)小，所(suo)以，開(kai)(kai)關(guan)管Q1的(de)(de)(de)基極(ji)(ji)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)同(tong)樣不受(shou)交(jiao)(jiao)流(liu)(liu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)波動的(de)(de)(de)影響，這就(jiu)展寬了開(kai)(kai)關(guan)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)海對交(jiao)(jiao)流(liu)(liu)輸人(ren)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)的(de)(de)(de)適應范圍。

　　二、開(kai)(kai)關中(zhong)楦流(liu)(liu)源(yuan)(yuan)(yuan)(yuan)電(dian)(dian)(dian)(dian)路(lu)的(de)(de)(de)特點1.含(han)(han)恒(heng)(heng)流(liu)(liu)源(yuan)(yuan)(yuan)(yuan)的(de)(de)(de)開(kai)(kai)關電(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)與不含(han)(han)恒(heng)(heng)流(liu)(liu)源(yuan)(yuan)(yuan)(yuan)的(de)(de)(de)開(kai)(kai)關電(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)的(de)(de)(de)電(dian)(dian)(dian)(dian)路(lu)區別通過(guo)對(dui)含(han)(han)恒(heng)(heng)流(liu)(liu)源(yuan)(yuan)(yuan)(yuan)開(kai)(kai)關電(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)和不含(han)(han)恒(heng)(heng)流(liu)(liu)源(yuan)(yuan)(yuan)(yuan)開(kai)(kai)關電(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)的(de)(de)(de)電(dian)(dian)(dian)(dian)路(lu)對(dui)比，就會發現，這兩類電(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)的(de)(de)(de)振(zhen)蕩(dang)反(fan)(fan)饋(kui)(kui)(kui)支(zhi)路(lu)的(de)(de)(de)阻(zu)抗(kang)是(shi)不同的(de)(de)(de)（反(fan)(fan)饋(kui)(kui)(kui)支(zhi)路(lu)主要(yao)由電(dian)(dian)(dian)(dian)阻(zu)和電(dian)(dian)(dian)(dian)容(rong)串聯組成）。附表(biao)是(shi)這兩類電(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)幾種(zhong)機心彩電(dian)(dian)(dian)(dian)反(fan)(fan)饋(kui)(kui)(kui)電(dian)(dian)(dian)(dian)容(rong)和反(fan)(fan)饋(kui)(kui)(kui)電(dian)(dian)(dian)(dian)阻(zu)的(de)(de)(de)統計表(biao)。從統計表(biao)中(zhong)可以(yi)看出：含(han)(han)恒(heng)(heng)流(liu)(liu)源(yuan)(yuan)(yuan)(yuan)的(de)(de)(de)開(kai)(kai)關電(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)振(zhen)蕩(dang)反(fan)(fan)饋(kui)(kui)(kui)電(dian)(dian)(dian)(dian)容(rong)小，阻(zu)抗(kang)大(da)，反(fan)(fan)饋(kui)(kui)(kui)電(dian)(dian)(dian)(dian)流(liu)(liu)小；不含(han)(han)恒(heng)(heng)流(liu)(liu)源(yuan)(yuan)(yuan)(yuan)的(de)(de)(de)開(kai)(kai)關電(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)振(zhen)蕩(dang)反(fan)(fan)饋(kui)(kui)(kui)電(dian)(dian)(dian)(dian)容(rong)大(da)，阻(zu)抗(kang)小，反(fan)(fan)饋(kui)(kui)(kui)電(dian)(dian)(dian)(dian)流(liu)(liu)大(da)。

　　2.失效后機(ji)器的故(gu)障(zhang)表現開關電(dian)(dian)(dian)(dian)源中的恒流(liu)電(dian)(dian)(dian)(dian)路失效后，注人開關管的基(ji)極電(dian)(dian)(dian)(dian)流(liu)僅有振(zhen)蕩反饋支路一路電(dian)(dian)(dian)(dian)流(liu)，只(zhi)能維持開關管處(chu)于弱振(zhen)蕩狀態，開關電(dian)(dian)(dian)(dian)源的負載(zai)能力(li)將會大(da)大(da)降低。遙(yao)控(kong)彩(cai)電(dian)(dian)(dian)(dian)在待電(dian)(dian)(dian)(dian)子世界(jie)老式(shi)彩(cai)電(dian)(dian)(dian)(dian)加(jia)裝哞技討嫡(di)t媒葙(xiang)f鯰(nian)改良方鉉李超2.記錄數據安裝前測量(liang)并記錄彩(cai)電(dian)(dian)(dian)(dian)各模擬量(liang)的電(dian)(dian)(dian)(dian)壓調節板±的運放。農彩(cai)電(dian)(dian)(dian)(dian)中模擬量(liang)控(kong)制(zhi)電(dian)(dian)(dian)(dian)壓的兩個指標彩(cai)電(dian)(dian)(dian)(dian)中有音量(liang)、亮度等模擬量(liang)控(kong)制(zhi)電(dian)(dian)(dian)(dian)路，它(ta)們一般用調節電(dian)(dian)(dian)(dian)壓的方式(shi)進(jin)行(xing)控(kong)制(zhi)。在這種電(dian)(dian)(dian)(dian)路中，控(kong)制(zhi)電(dian)(dian)(dian)(dian)壓有兩個指標。

　　調節范(fan)圍設電(dian)(dian)(dian)位器調到(dao)上、下(xia)極限時(shi)，對應(ying)的觸頭電(dian)(dian)(dian)位分別為Vh、Vl，則控(kong)制電(dian)(dian)(dian)壓調節范(fan)圍AV=VH―VL.一(yi)般來說厶V越(yue)大控(kong)制范(fan)圍越(yue)寬。但是(shi)，過大的AV會使調節精度下(xia)降，影(ying)響圖像或(huo)伴(ban)音(yin)質量，嚴重時(shi)彩電(dian)(dian)(dian)不能(neng)正常工作(zuo)。

　　平(ping)均(jun)(jun)電(dian)位平(ping)均(jun)(jun)電(dian)位丫=丫11一￥1/2.丫的(de)大小直接影響控制效(xiao)果。如飽和度控制中，V過小會造(zao)成圖(tu)像飽和度調(diao)不起來(lai)，色彩很淡。所以在加裝(zhuang)遙控時，AV和V應(ying)盡可能調(diao)整到(dao)設計水平(ping)。如有困難，以適當偏(pian)高為(wei)宜。

　　改良(liang)方(fang)法(fa)的基本(ben)構想1.模擬量控制(zhi)(zhi)電(dian)路(lu)的特點老式彩電(dian)一般有四(si)個模擬量，如遙控板上(shang)(shang)有四(si)個相應的模擬量輸出(chu)(chu)電(dian)路(lu)，各由三(san)只電(dian)阻：輸出(chu)(chu)電(dian)阻，上(shang)(shang)、下偏置電(dian)阻組成，在中(zhong)相應的電(dian)阻分別是R17、R18、R19.其中(zhong)，輸出(chu)(chu)電(dian)阻主要控制(zhi)(zhi)調節范圍，上(shang)(shang)、下偏置電(dian)阻主要控制(zhi)(zhi)平均電(dian)位。

　　2.現行的(de)調(diao)整(zheng)(zheng)(zheng)(zheng)方法及改(gai)良安裝說明書及一(yi)般資(zi)料上介紹的(de)方法是，廢除彩電(dian)原有的(de)分壓調(diao)節電(dian)路(lu)，對遙控板上的(de)電(dian)阻(zu)(zu)進行調(diao)整(zheng)(zheng)(zheng)(zheng)。這樣(yang)須調(diao)整(zheng)(zheng)(zheng)(zheng)的(de)電(dian)阻(zu)(zu)一(yi)般有12只。在實際工作中要選定并找到(dao)相應(ying)的(de)電(dian)阻(zu)(zu)并不(bu)容易，調(diao)整(zheng)(zheng)(zheng)(zheng)起來(lai)反反復(fu)復(fu)，耗時(shi)多，精(jing)度差(cha)。

　　從上面(mian)的(de)分(fen)析(xi)中，我們不難發現(xian)：如果保(bao)留(liu)彩(cai)電(dian)上的(de)分(fen)壓(ya)電(dian)路(lu)就可以省掉遙控板(ban)上的(de)分(fen)壓(ya)電(dian)路(lu)，這樣需調整(zheng)的(de)電(dian)阻由12只減為4只，大大減少了工作(zuo)量，有利于提高(gao)調整(zheng)精(jing)度。

　　實例(li)-1803PD（S）彩電(dian)(dian)(dian)安裝卓異Z9831遙控器為例(li)，現(xian)介(jie)紹(shao)如下(xia)：1.準(zhun)備材料(liao)找51kn、200kfl可(ke)調電(dian)(dian)(dian)阻各一只，按(an)連接，引線(xian)長約30cm.備1/8W電(dian)(dian)(dian)阻若干(gan)。機狀態，行(xing)、場(chang)掃(sao)描(miao)電(dian)(dian)(dian)路停(ting)止(zhi)工(gong)(gong)作(zuo)，開(kai)(kai)關(guan)電(dian)(dian)(dian)源(yuan)(yuan)處于輕負(fu)(fu)(fu)荷狀態，即使恒流有(you)問題也(ye)看不出它的(de)(de)故障表現(xian)。當(dang)電(dian)(dian)(dian)視(shi)機處于正常收視(shi)狀態，特別是電(dian)(dian)(dian)視(shi)屏(ping)幕比(bi)較亮時，行(xing)、場(chang)掃(sao)描(miao)系統(tong)要消耗較大的(de)(de)功率，恒流源(yuan)(yuan)失(shi)效了的(de)(de)開(kai)(kai)關(guan)電(dian)(dian)(dian)源(yuan)(yuan)難(nan)以負(fu)(fu)(fu)擔這(zhe)一重(zhong)(zhong)任，開(kai)(kai)關(guan)電(dian)(dian)(dian)源(yuan)(yuan)將會停(ting)止(zhi)工(gong)(gong)作(zuo)。開(kai)(kai)關(guan)電(dian)(dian)(dian)源(yuan)(yuan)停(ting)止(zhi)工(gong)(gong)作(zuo)后，行(xing)、場(chang)掃(sao)描(miao)電(dian)(dian)(dian)路因失(shi)去(qu)供電(dian)(dian)(dian)也(ye)自然停(ting)止(zhi)工(gong)(gong)作(zuo)，這(zhe)時開(kai)(kai)關(guan)電(dian)(dian)(dian)源(yuan)(yuan)因失(shi)去(qu)負(fu)(fu)(fu)載(zai)又(you)(you)開(kai)(kai)始起振(zhen)工(gong)(gong)作(zuo)，行(xing)、場(chang)掃(sao)描(miao)又(you)(you)得(de)到(dao)供電(dian)(dian)(dian)再度工(gong)(gong)作(zuo)，開(kai)(kai)關(guan)管負(fu)(fu)(fu)擔加重(zhong)(zhong)又(you)(you)停(ting)止(zhi)工(gong)(gong)作(zuo)，周而復始，范圍，留作(zuo)調試標準(zhun)。實測數(shu)據為：亮度：7.4彩電(dian)(dian)(dian)電(dian)(dian)(dian)路改動關(guan)掉彩電(dian)(dian)(dian)電(dian)(dian)(dian)源(yuan)(yuan)拔下(xia)插頭(tou)，將各模(mo)擬量(liang)的(de)(de)控制端由電(dian)(dian)(dian)位(wei)器的(de)(de)中心抽頭(tou)改接到(dao)電(dian)(dian)(dian)位(wei)器的(de)(de)高電(dian)(dian)(dian)位(wei)端，并與遙控板上相應模(mo)擬量(liang)的(de)(de)輸出引線(xian)庫接，如所示。

　　4遙控(kong)板(ban)調整拔(ba)下遙控(kong)板(ban)上(shang)(shang)各模(mo)擬量(liang)輸出(chu)端的上(shang)(shang)下偏置電阻共8只，在(zai)其它加(jia)裝工(gong)作已完成的情況下，對各模(mo)擬量(liang)的輸出(chu)電阻進行調整。以亮(liang)(liang)度控(kong)制(zhi)為(wei)例，具體步驟如下：⑴拔(ba)下輸出(chu)電阻R17，將51M1可調電阻焊(han)上(shang)(shang)，通電并用遙控(kong)將亮(liang)(liang)度調到最小。如果熒光屏不(bu)亮(liang)(liang)，可用萬用表監測(ce)亮(liang)(liang)度控(kong)制(zhi)電壓，下降到不(bu)動為(wei)止。

　　（2）調(diao)(diao)(diao)(diao)整51kfi可(ke)調(diao)(diao)(diao)(diao)電(dian)阻(zu)(zu)(zu)使亮(liang)度(du)控制電(dian)壓為7.4V.關機(ji)(ji)焊(han)下可(ke)調(diao)(diao)(diao)(diao)電(dian)阻(zu)(zu)(zu)的一端，測(ce)(ce)得其阻(zu)(zu)(zu)值為37kfl.⑶重新焊(han)上可(ke)調(diao)(diao)(diao)(diao)電(dian)阻(zu)(zu)(zu)并(bing)開機(ji)(ji)，用(yong)遙控器將亮(liang)度(du)調(diao)(diao)(diao)(diao)到最大。調(diao)(diao)(diao)(diao)整可(ke)調(diao)(diao)(diao)(diao)電(dian)阻(zu)(zu)(zu)使亮(liang)度(du)控制電(dian)壓為7.9V，關機(ji)(ji)焊(han)下可(ke)調(diao)(diao)(diao)(diao)電(dian)阻(zu)(zu)(zu)，測(ce)(ce)得其阻(zu)(zu)(zu)值為40kft.在(zai)步(bu)驟(zou)⑵、⑶中。如果調(diao)(diao)(diao)(diao)整可(ke)調(diao)(diao)(diao)(diao)電(dian)阻(zu)(zu)(zu)達不到所(suo)需電(dian)壓，就將可(ke)調(diao)(diao)(diao)(diao)電(dian)阻(zu)(zu)(zu)由(you)51kfl換成200M1后重試。

　　⑷一(yi)般來說(shuo)，選(xuan)(xuan)擇偏小的輸(shu)出電阻使調節范圍適當擴(kuo)大(da)為(wei)宜，這里選(xuan)(xuan)R17=36kft.經(jing)測試(shi)亮度控制電壓為(wei)7.3~8.IV，效果很理想。如(ru)果選(xuan)(xuan)R17=33kft，效果也(ye)不(bu)錯。其(qi)它三個模擬量輸(shu)出電阻的選(xuan)(xuan)擇方法與此相同，這里不(bu)再贅述(shu)。

　　從上(shang)面的(de)(de)介紹(shao)中(zhong)不難發現(xian)這種方法有(you)三個優點：（1）不需對電(dian)(dian)(dian)(dian)路進行太多分析和了(le)解(jie)。⑵需要調(diao)整(zheng)電(dian)(dian)(dian)(dian)阻(zu)(zu)由12只變成4只，減(jian)少了(le)工(gong)作量。⑶調(diao)整(zheng)精度(du)便于控(kong)制(zhi)，有(you)利于提(ti)高圖(tu)像(xiang)(xiang)質量。必須說明的(de)(de)是，這里介紹(shao)的(de)(de)；1一(yi)般性的(de)(de)方法，在實際工(gong)作中(zhong)應(ying)靈活(huo)運用(yong)(yong)。例如(ru)，在對本例的(de)(de)音(yin)量控(kong)制(zhi)電(dian)(dian)(dian)(dian)路進行連(lian)接(jie)時(shi)(shi)，可(ke)將遙控(kong)板上(shang)的(de)(de)三只電(dian)(dian)(dian)(dian)阻(zu)(zu)R11、R12、R13拔掉(diao)，將電(dian)(dian)(dian)(dian)視機(ji)中(zhong)的(de)(de)R302移(yi)到(dao)遙控(kong)板上(shang)R11的(de)(de)位置，如(ru)所示，則音(yin)量控(kong)制(zhi)電(dian)(dian)(dian)(dian)壓為0~5.6V，效果不錯。對于控(kong)制(zhi)電(dian)(dian)(dian)(dian)壓為0~12V的(de)(de)電(dian)(dian)(dian)(dian)路，如(ru)夏普NC-2T的(de)(de)色度(du)和對比度(du)控(kong)制(zhi)電(dian)(dian)(dian)(dian)路，可(ke)將遙控(kong)板輸出端的(de)(de)上(shang)、下偏(pian)置電(dian)(dian)(dian)(dian)阻(zu)(zu)拔掉(diao)，將輸出電(dian)(dian)(dian)(dian)阻(zu)(zu)換成l~2kft即可(ke)使(shi)用(yong)(yong)。這時(shi)(shi)輸出電(dian)(dian)(dian)(dian)阻(zu)(zu)僅起限流作用(yong)(yong)，以保護遙控(kong)開(kai)關(guan)電(dian)(dian)(dian)(dian)源只能(neng)處于間歇(xie)振蕩(dang)狀態(tai)。表(biao)現(xian)在電(dian)(dian)(dian)(dian)視屏幕上(shang)的(de)(de)故障現(xian)象是：電(dian)(dian)(dian)(dian)視屏幕亮(liang)度(du)高時(shi)(shi)，光柵(zha)會不斷地收(shou)縮。或(huo)者當電(dian)(dian)(dian)(dian)視畫面較(jiao)暗(an)時(shi)(shi)，圖(tu)像(xiang)(xiang)尚能(neng)穩定(ding)住。當電(dian)(dian)(dian)(dian)視畫面較(jiao)亮(liang)時(shi)(shi)，就會出現(xian)“光柵(zha)不停地收(shou)縮――展(zhan)開(kai)一(yi)收(shou)縮”。這時(shi)(shi)你測量+B115V電(dian)(dian)(dian)(dian)壓，在光柵(zha)收(shou)縮瞬間會降至70V左右。該(gai)電(dian)(dian)(dian)(dian)視機(ji)在調(diao)機(ji)進行搜(sou)索(suo)時(shi)(shi)，搜(sou)索(suo)到(dao)的(de)(de)圖(tu)像(xiang)(xiang)比較(jiao)暗(an)時(shi)(shi)，可(ke)以正(zheng)常搜(sou)索(suo)并(bing)存儲(chu)。搜(sou)索(suo)到(dao)的(de)(de)圖(tu)像(xiang)(xiang)較(jiao)亮(liang)時(shi)(shi)，光柵(zha)來回閃動，圖(tu)像(xiang)(xiang)不穩定(ding)，或(huo)同(tong)步不良，電(dian)(dian)(dian)(dian)視頻道不能(neng)存儲(chu)。

                                                                                                                   本(ben)文摘(zhai)自于中國鋰電網(wang)