用ET521A对长虹D2962A彩电黑屏的检修

伊万视波

接修一台长虹D2962A彩电,故障为黑屏,有声音.
检修:接手之后,开机,有声音,灯丝亮,判断故障点在场部分.
---用ET521A自动示波现场综合检测仪（以下简称ET521A）的电阻挡在路测量场块IC//TDA3654的各引脚数据:1(157.9K),2(O.O),3(157.6K),4(0.0),5(474.9K),6(6.16K),7((不通),8(391.0),9((1.8K)
---用ET521A的电压挡测在有信号输入时TDA3654的各脚数据： （V)--1(3.35V),2(0.0V),3(3.35V),4(0.0V),5(36.07V),6(37.57V),7(5.44V),8(0.0V),9(38.17).--------------特点:黑屏.
---用ET521A的电压档测在无信号输入时TDA3654的各脚数据： （V)--1(3.34V),2(0.0V),3(3.35V),4(0.0V),5(36.07V),6(37.61V),7(6.07V),8(0.0V),9(38.17V).
---用ET521A的OSC(波形)挡测各脚数据:有信号输入时:1(+UP:3.5V,-UP:3.4V,VP-P:80MV,频率:18.50KHZ,周期:54.04US)
---------------------------------------------------2(+UP:40MV,-UP:-120MV,VP-P:80MV,频率:0.0HZ,周期:4.29US)
---------------------------------------------------3(+UP:3.5V,-UP:3.4V,VP-P:80MV,频率:109.11KHZ,周期:9.16US)
---------------------------------------------------4(同第二脚)
---------------------------------------------------5(+UP:-40MV,-UP:160MV,VP-P:120MV,频率:0.0HZ,周期:4.29US)
----------------------------------------------------6(+(UP:5.0V,-UP:5.0V,VP-P:0MV,频率:0.0HZ,周期:4.29US)
----------------------------------------------------7(同第6脚)
----------------------------------------------------8(+UP:-80MV,-UP:-160MV,VP-P:80MV,频率:0.0HZ,周期:4.29US)
----------------------------------------------------9(+UP:120MV,-UP:40MV,VP-P:80MV,频率:0.0HZ,周期:4.29US)
经过电压的测量,和以往的数据对比,在对外部元器件检查未见异常之后,果断换下TDA3654,彩电恢复正常.
---正常时的数据(有信号输入),(V):1(2.89V),2.和4(0.0V),3(2.89V),5(14.45V),6(36.49V),7(0.001V),8(5.79V),9(36.19V).
---正常时的波形(有信号输入),1(+UP:2.6V,-UP:2.4V,VP-P:200MV)
---------------------------2(+UP:-40MV,-UP:-120MV,VP-P:80MV)
---------------------------3(+UP:2.4V,-UP:2.2V,VP-P:160MV)
---------------------------4(同2)
---------------------------5(+UP:5.0V,-UP:5.0V,VP-P:0MV,)
---------------------------6(同5)
---------------------------7(+UP:-40MV,-UP:-120MV,VP-P:80MV)
---------------------------8(+UP:5.0V,-UP:5.0V,VP-P:0MV)
---------------------------9(同8)

[ 本帖最后由 伊万视波 于 2009-2-13 16:29 编辑 ]

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